Lower case some feature gate error messages

[mark-i-m]

No description provided.

[rust-highfive]

r? @petrochenkov

(rust_highfive has picked a reviewer for you, use r? to override)

[zackmdavis]

This could be squashed into one commit.

[petrochenkov]

r=me after squashing
@bors delegate+

[bors]

✌️ @mark-i-m can now approve this pull request

[mark-i-m]

Squashed. Will wait for travis. Then r+

[mark-i-m]

@bors r+

[bors]

📌 Commit 9f6bdb9 has been approved by mark-i-m

[bors]

⌛ Testing commit 9f6bdb9 with merge a50bdee8c46dec974d219c492bbdc79cde613289...

[bors]

💔 Test failed - status-travis

[rust-highfive]

The job x86_64-gnu-tools of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

  0     0    0     0    0     0      0      0 --:--:--  0:00:51 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:52 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:53 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:54 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:55 --:--:--     0curl: (6) Could not resolve host: s3-us-west-1.amazonaws.com
[01:07:10] thread 'main' panicked at 'failed to download openssl source: exit code: 6', bootstrap/native.rs:589:17
[01:07:10] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --no-fail-fast src/doc/book src/doc/nomicon src/doc/reference src/doc/rust-by-example src/tools/rls src/tools/rustfmt src/tools/miri src/tools/clippy
[01:07:10] Build completed unsuccessfully in 1:04:20
[01:07:10] {"miri":"test-pass","clippy-driver":"test-pass","rust-by-example":"test-pass","rustfmt":"test-pass","book":"test-pass","reference":"test-pass","rls":"test-pass","nomicon":"test-pass"}
[01:07:10] Verifying status of book...
---
travis_time:end:06770e00:start=1530083686967287405,finish=1530083686972872661,duration=5585256
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0e00674c
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:01a58d38
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[rust-highfive]

The job x86_64-gnu-tools of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

  0     0    0     0    0     0      0      0 --:--:--  0:00:51 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:52 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:53 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:54 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:55 --:--:--     0curl: (6) Could not resolve host: s3-us-west-1.amazonaws.com
[01:07:10] thread 'main' panicked at 'failed to download openssl source: exit code: 6', bootstrap/native.rs:589:17
[01:07:10] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --no-fail-fast src/doc/book src/doc/nomicon src/doc/reference src/doc/rust-by-example src/tools/rls src/tools/rustfmt src/tools/miri src/tools/clippy
[01:07:10] Build completed unsuccessfully in 1:04:20
[01:07:10] {"miri":"test-pass","clippy-driver":"test-pass","rust-by-example":"test-pass","rustfmt":"test-pass","book":"test-pass","reference":"test-pass","rls":"test-pass","nomicon":"test-pass"}
[01:07:10] Verifying status of book...
---
travis_time:end:06770e00:start=1530083686967287405,finish=1530083686972872661,duration=5585256
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0e00674c
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:01a58d38
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[kennytm]

@bors retry travis-ci/travis-ci#9696

[pietroalbini]

@bors rollup