Disable integration tests due to golang build failure

.travis.yml

@@ -56,6 +56,9 @@ script:
   - make
   - make check
   - cd integration-tests
-  - export GOPATH="$PWD/integration-tests/golang"
+  # As of April, 23, 2016, golang http2 build fails, probably because
-  - make itprep
+  # the default go version is too old.
-  - make it
+
+  # - export GOPATH="$PWD/integration-tests/golang"
+  # - make itprep
+  # - make it