Changes to row-batch.cc and Data.thrift interface.

This change will allow row-batch.cc to use LZ4 codec.
It will be implemented in a following patch.

Change-Id: I9302da1b72c83fcf8420724138d40ad0d82c554b
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3030
Reviewed-by: Paden Tomasello <paden.tomasello@cloudera.com>
Tested-by: jenkins