Fix compile error on test cases on loader project.

Currently, `sbt "project loader" test:compile` fail.
Following test cases fail because it did not catch up changes from s2core.

1. GraphSubscriberTest
2. TransferToHFileTest,

Current test case expect s2rest_play server up and running even though it is not necessary. We should refactor code on loader so we can easily inject meta data on test cases.

As we discussed on mailing list, I suggest just comment out these test cases, for the first release, then create separate issue for writing better test cases for loader project.