MB-100: fix libvbucket branch

Change-Id: I696f0b32a2d2745307d082a527f926572458ada6
Reviewed-on: http://review.couchbase.org/27992
Reviewed-by: Junyi Xie <junyi.couchbase@gmail.com>
Tested-by: Junyi Xie <junyi.couchbase@gmail.com>