convert index type to uint64
convert index type to uint64

Change-Id: If0568d6db4e1631a1a0dd7e01753165c1fa29988
Reviewed-on: http://review.couchbase.org/30771
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

couchbase/cbmonitor,couchbase/cbmonitor