Stop testing travis against other gemfiles

This has been failing for a while and hasn't been useful.

Author: oestrich

.travis.yml

@@ -6,9 +6,6 @@ rvm:
   - 2.2
 gemfile:
   - Gemfile
-  - gemfiles/rspec-3.0.x.gemfile
-  - gemfiles/rspec-3.1.x.gemfile
-  - gemfiles/rspec-3.2.x.gemfile
 script:
   - bundle exec rake
 branches: