Auto merge of #4270 - behnam:ignore, r=alexcrichton
authorbors <bors@rust-lang.org>
Tue, 18 Jul 2017 16:04:11 +0000 (16:04 +0000)
committerbors <bors@rust-lang.org>
Tue, 18 Jul 2017 16:04:11 +0000 (16:04 +0000)
[sources/path] Add gitignore-like pattern matching and warn on mismatches

Add gitignore-like pattern matching logic to `list_files()` and throw
warnings for paths getting different inclusion/exclusion results from
the old and the new methods.

Migration Tracking: <#4268>


Trivial merge