[travis] Don't install bundle groups we don't need for a test run.

.travis.yml

 language: objective-c
 env:
   # This is what 10.8.x comes with and we want to support that.
-  - RVM_RUBY_VERSION=system NOEXEC_DISABLE=1 XCODEPROJ_BUILD=1 RUBY_VERSION_SPECIFIC='sudo ln -s /usr/bin/llvm-gcc-4.2 /usr/bin/gcc-4.2' SSL_CERT_FILE=/usr/local/share/cacert.pem GIT_AUTHOR_NAME=CocoaPods GIT_AUTHOR_EMAIL=cocoapods@example.com PYTHONPATH=/usr/local/lib/python2.7/site-packages
-  - RVM_RUBY_VERSION=2.0.0-p247 NOEXEC_DISABLE=1 XCODEPROJ_BUILD=1 RUBY_VERSION_SPECIFIC='sudo gem install bundler --no-ri --no-rdoc' GIT_AUTHOR_NAME=CocoaPods GIT_AUTHOR_EMAIL=cocoapods@example.com PYTHONPATH=/usr/local/lib/python2.7/site-packages
+  - RVM_RUBY_VERSION=system NOEXEC_DISABLE=1 XCODEPROJ_BUILD=1 BUNDLE_WITHOUT='debugging:documentation' RUBY_VERSION_SPECIFIC='sudo ln -s /usr/bin/llvm-gcc-4.2 /usr/bin/gcc-4.2' SSL_CERT_FILE=/usr/local/share/cacert.pem GIT_AUTHOR_NAME=CocoaPods GIT_AUTHOR_EMAIL=cocoapods@example.com PYTHONPATH=/usr/local/lib/python2.7/site-packages
+  - RVM_RUBY_VERSION=2.0.0-p247 NOEXEC_DISABLE=1 XCODEPROJ_BUILD=1 BUNDLE_WITHOUT='debugging:documentation' RUBY_VERSION_SPECIFIC='sudo gem install bundler --no-ri --no-rdoc' GIT_AUTHOR_NAME=CocoaPods GIT_AUTHOR_EMAIL=cocoapods@example.com PYTHONPATH=/usr/local/lib/python2.7/site-packages
 before_install:
   - curl http://curl.haxx.se/ca/cacert.pem -o /usr/local/share/cacert.pem
   # - sh -c 'if [ "$RVM_RUBY_VERSION" != "system" ]; then rvm install $RVM_RUBY_VERSION --without-tcl --without-tk; fi'