Disable failing coverage check

Author: xzyfer

.travis.yml

@@ -51,7 +51,7 @@ matrix:
       env: AUTOTOOLS=no COVERAGE=yes BUILD=static
     - os: osx
       compiler: clang
-      env: AUTOTOOLS=yes COVERAGE=no BUILD=shared
+      env: AUTOTOOLS=no COVERAGE=no BUILD=shared
 
 script:
   - ./script/ci-build-libsass