Use cmake branch for memcached in toy/trond.xml

Change-Id: I0ad6687a3858ae6cac08589736a4e7ca073d2fc5
Reviewed-on: http://review.couchbase.org/28570
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>