lcb_remove3_cmd => lcb_CMDREMOVE

Change-Id: I8f7173ba1519faf2c1280ac4f220d54c3b0ceec0
Reviewed-on: http://review.couchbase.org/38087
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>