[travis] do not build clang on osx

Summary:
This restores the functionality from before D5208622: we didn't use to build
clang on osx because Travis does not allow enough time for the build process to
finish.

Reviewed By: mbouaziz

Differential Revision: D5292233

fbshipit-source-id: 0b6573d

.travis.yml

@@ -11,7 +11,7 @@ before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install opam; fi
 install:
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then travis_wait 120 ./build-infer.sh --yes; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then travis_wait 60 ./build-infer.sh --yes --java; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then eval `opam config env`; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then opam pin add -y --no-action -k git infer .; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then opam install -y infer; fi