Fix typo in name of design document remove function.

Change-Id: Ic12fde3f309f74dbc9355d19239e8d80f6396b47
Reviewed-on: http://review.couchbase.org/41425
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Brett Lawson <brett19@gmail.com>