Cast the 0 in assignment to the type

Change-Id: I201bea9d39d9b93dbce2c57f08ba91c2ce6e5679
Reviewed-on: http://review.couchbase.org/31195
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>