Coveralls fix. (#1403)

Author: mbutrovich

.travis.yml

@@ -87,4 +87,4 @@ script:
     - if [[ $TRAVIS_OS_NAME != 'osx' ]]; then python ../script/testing/junit/run_junit.py; fi
     - if [[ $TRAVIS_OS_NAME == 'osx' ]]; then ASAN_OPTIONS=detect_container_overflow=0 python ../script/testing/junit/run_junit.py; fi
     # upload coverage info
-    - if [[ $TRAVIS_OS_NAME == 'On' ]]; then make coveralls; fi
+    - if [[ $COVERALLS == 'On' ]]; then make coveralls; fi