Expand VBucket::commit error message
Expand VBucket::commit error message

Include the prepared and committed seqno in the message to aid in debugging.

Change-Id: I5f2ed355f57647e7ba8e3f5fa8fec8feffb64b7b
Reviewed-on: http://review.couchbase.org/114123
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: James Harrison <5c25a7b3db09830813688775bfc8e6de736a230c@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine