lcbio: Unify error callback

Change-Id: I5c72d75beb0e28743e4be1995b5cdf6c88f47d77
Reviewed-on: http://review.couchbase.org/33579
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>