So basically g.addV() is adding vertices in hbase server. But retrieval after restart of gremlin is not happening. 
Step1. In gremlin console, g2.addV() and g2.V().count() returns 124

Step2: Restart gremlin conosole and run g2.V().count()

gremlin> g2.V().count()

14:04:54 WARN  org.janusgraph.graphdb.transaction.StandardJanusGraphTx  - Query requires iterating over all vertices [()]. For better performance, use indexes

==>123

This is still the old value.

Howe ver same works with janusgraph-0.6.0