Fix Travis breaking due to dependency conflict.

Supplies a temporary solution to current Travis builds breaking for Rexster.  Possibly caused by dependency conflict between blueprints-core 2.6 and blueprints core 2.7.0-SNAPSHOT.   

I'm guessing the version was left at 2.6 because the dependency for  frames 2.7.0-SNAPSHOT is apparently missing:

    [ERROR] Failed to execute goal on project frames-kibble: Could not resolve dependencies for project 
     com.tinkerpop.rexster.rexster-kibbles:frames-kibble:jar:2.7.0-SNAPSHOT: Could not find artifact
     com.tinkerpop:frames:jar:2.7.0-SNAPSHOT in sonatype-snapshots.