[Box Backup-commit] [boxbackup/boxbackup] c4bee4: Travis config: exclude GCC builds on OSX

[GitHub]

  Branch: refs/heads/s3_support
  Home:   https://github.com/boxbackup/boxbackup
  Commit: c4bee4fa3046f59f879cdc58afca3fabc5087f50
      https://github.com/boxbackup/boxbackup/commit/c4bee4fa3046f59f879cdc58afca3fabc5087f50
  Author: Chris Wilson <chris+github at qwirx.com>
  Date:   2016-12-25 (Sun, 25 Dec 2016)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Travis config: exclude GCC builds on OSX

There's no point testing both GCC and Clang on Mac OS X, as they're the same
thing.