Add suppress rule for Tachyon *Conf classes

Since PR #473 we support mvn checkstyle to check style using Google Java style.

This PR adds suppress rule for Tachyon *Conf classes to exempt the public final members as all upper cases.
We will remove the exempt file once new Configuration [1] is implemented.

Once this one is merged, I will submit PR to modify the build to break whenever checkstyle fail to integrate it as part of Jenkins CI.

[1] https://tachyon.atlassian.net/browse/TACHYON-8