MB-9859: Use numeric_limits instead of a hex number for uint64_t max

Change-Id: I19259f6c0126d9aa60f25ea487f9971dad59e2c3
Reviewed-on: http://review.couchbase.org/31739
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>