Fix clippy warning: next() instead of nth(0)

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Merge branch 'replace-failure-with-anyhow'

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Replace failure with anyhow in complete codebase

This patch was scripted with

    sed -i 's/use failure::Error/use anyhow::Error/' $(rg "use failure::Error" -l)
    sed -i 's/use failure::Fallible as /use anyhow::/' $(rg "use failure::Fallible" -l)
    sed -i 's/failure/anyhow/' $(rg "failure *=" -l)
    sed -i 's/format_err!/anyhow!/' $(rg "format_err!" -l)
    sed -i 's/use failure::ResultExt/use anyhow::Context/' $(rg "use failure::ResultExt" -l)
    sed -i 's/err_msg/anyhow!/' $(rg "use failure::err_msg" -l)
    sed -i 's/^anyhow\ *=.*$/anyhow = "1"/' $(rg "anyhow * =" -l)
    sed -i 's/^anyhow_derive.*//' $(rg "anyhow_derive" -l)
    sed -i 's/extern crate failure/extern crate anyhow/' $(rg "extern crate failure" -l)
    sed -i 's/.*extern crate anyhow_derive.*//' $(rg "anyhow_derive" -l)

Some manual changes were added as well, so this patch was not completely
scripted, but mostly.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Update copyright years to 2015-2020

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Pull changes from https://github.com/flip1995/imag clippy_fix

This pulls in the clippy fixes from Phil. From the request-pull:

-----8<-----
    I finally got to fixing all of the Clippy warnings in the imag codebase.
    `cargo test` passes, `cargo clippy` doesn't produce any warnings
    or errors.

    Some important notes:
      - I didn't pay attention to the line length of the changes, so it may
        have happened that some lines are now longer than 100 chars
      - Except two commits the commit messages are formatted as follows:
        * The first tag shows if the changes in the commit were
          automatically applied by `cargo fix --clippy -Zunstable-options`.
          Commits that were automatically applied may require closer review,
          since I didn't check those by hand and the Clippy fix feature is
          still unstable.
        * The other tags specify the subcrate that is affected by the
          commit. I created one commit for each subcrate, even when only one
          file (most of the time the `main.rs` file) was changed.
      - I created one commit, where I replace usages of `r#try!` with the
        `?` operator, since `try!` is now officially deprecated.
      - I created one commit, where I just allow Clippy lints. Either because
        the fix would require much more work or knowledge of the codebase or
        because it was a FP.

    This was pretty much work, but it helped detecting a few bugs in Clippy,
    where I was already able to open 3 or 4 PRs. So win-win I guess.

    [...] we got a net LoC decrease.
----->8-----

[No-auto] lib/core/rt: Fix Clippy warnings

Signed-off-by: flip1995 <hello@philkrones.com>
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

[Auto] lib/core/rt: Fix Clippy warnings

Signed-off-by: flip1995 <hello@philkrones.com>
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Remove use of Itertools

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Fix for rust beta compiler

The beta compiler reports duplicated input:

error: the item `IntoValues` is imported redundantly
   --> lib/entry/libimagentrylink/src/internal.rs:398:13
    |
36  | use self::iter::IntoValues;
    |     ---------------------- the item `IntoValues` is already imported here
...
398 |         use internal::iter::IntoValues;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |

so we fix this here.

Other imports were fixed as well.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Adapt for new interface of gen_vars() function

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Remove clone() calls

We should be able, from the signature of the `generate_variants()`
helper function, to pass a `Vec<&T>` here, so cloning should not be
necessary.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Fix config override mechanism

The bug was that we did not actually _set_ the new value.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Update copyright years

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Merge branch 'failure'

I'm so happy to finally be able to merge this patchset. After four days
of work, we finally convert the whole codebase from error_chain error
handling to failure.

Dependencies are now imported from "master" or even "failure" branches,
which will result in dependencies breaking the imag build as soon as the
"failure" branches vanish or the master breaks on the dependencies, but
we do it anyways until we are in release-shape.

Thanks goes to Kai for emotional support during the last weekend while
developing this patchset.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

libimagrt: Move from error-chain to failure

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Merge pull request #1491 from matthiasbeyer/fix-rustc126-flatten-warning

Fix: Explicitely use Itertools::flatten()

Fix: Explicitely use Itertools::flatten()

As of rustc 1.26, the `flatten()` method on iterators is preserved by
the rust standard library.
This could cause this code to hard-error some time in the future with
the `flatten()` function actually implemented by the standard library.

Hence we move to use the `Itertools::flatten()` function here
explicitely.

Merge pull request #1446 from matthiasbeyer/travis-clippy

Travis: clippy

Change generate_variants() helper to use base by ref

Merge pull request #1274 from matthiasbeyer/refactor-error-handling

libimagerror: Refactor

Adapt libimagrt to new error handling