Ticket #342 - better error message when cache overflows
Description: commit 892bf12c1bb8b10afea3d6ff711059bf04e362cc
introduced an invalid memory read/write. This patch prepares one
extra aclpblock for the acl cache overflow.
https://fedorahosted.org/389/ticket/342
Reviewed by rmeggins@redhat.com (Thank you, Rich!!)