Print out the command name

Allow the user to specify the opcode by name or value

Change-Id: I5898257224b1d4786de4349fa93b2a94eca0755d
Reviewed-on: http://review.couchbase.org/35051
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>