Implement test for KeyInfoRequest

This patch change the format for the return message on
the key info request so that it looks like the other
commands as well.

Change-Id: Ibe921bbb3802e5e04c52fec62ab37b3c088328b8
Reviewed-on: http://review.couchbase.org/27912
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Trond Norbye <trond.norbye@gmail.com>