don't allow to use single-value inputs
don't allow to use single-value inputs

Change-Id: I547607eea943995fefb7816875541eab03b198cd
Reviewed-on: http://review.couchbase.org/32571
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

couchbase/cbmonitor,couchbase/cbmonitor