Allow OSX build to fail (till #364 is fixed)

.travis.yml

@@ -2474,7 +2474,7 @@ cache:
   - $HOME/third-party
 
 matrix:
-  fast_finish: true
+  fast_finish: false
   exclude:
     # Exclude GCC from OS X builds because it's actually clang so it's just duplicate builds
     - os: osx
@@ -2482,6 +2482,8 @@ matrix:
     # Exclude Linux from MACOSX_PACKAGE builds
     - os: linux
       env: MACOSX_PACKAGE=1
+  allow_failures:
+    - os: osx
 
 script:
   - if [ "${MACOSX_PACKAGE}" == "1" ]; then