Update .travis.yml

remove dead code.

.travis.yml

@@ -23,11 +23,6 @@ env:
     - LINUX=1 TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF
     - LINUX=1 SHARED_BUILD=ON      ENABLE_COVERALLS=OFF
     - LINUX=1 SHARED_BUILD=OFF     ENABLE_COVERALLS=OFF
-    #exclude:
-    #    - os: linux
-    #      compiler: clang
-    #    - os: osx
-    #      compiler: gcc  
 
 compiler:
   - gcc