Don't abort on upr noop functions

These are getting called by a background task and causing crashes.
Let's just remove the aborts, but leave a comment that we will
implement those functions later.

Change-Id: I232af2e06afc9dd142680188178743bb0fc20d8f
Reviewed-on: http://review.couchbase.org/31235
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>