Cast the size to uint64_t to make it a known size
Cast the size to uint64_t to make it a known size

Not all platforms have the format specifier to print size_t

Change-Id: Iad3d15867e2d6953f274e51617223af4502f80c2
Reviewed-on: http://review.couchbase.org/31198
Reviewed-by: Volker Mische <fb414f8ac0dbbf87663550ae4ef5fc95b1041941@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

couchbaselabs/couchstore,t3rm1n4l/couchstore,t3rm1n4l/couchstore,abhinavdangeti/couchstore,abhinavdangeti/couchstore,couchbaselabs/couchstore,t3rm1n4l/couchstore,abhinavdangeti/couchstore,couchbaselabs/couchstore,vmx/couchstore,vmx/couchstore,jimwwalker/couchstore,jimwwalker/couchstore,jimwwalker/couchstore,vmx/couchstore