disable workers in tests with empty buckets
disable workers in tests with empty buckets

Change-Id: I988d4bbe0c423ab3caf2d6a159b21b15eae6e821
Reviewed-on: http://review.couchbase.org/38169
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>
Tested-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

dkao-cb/perfrunner,pavel-paulau/perfrunner,EricACooper/perfrunner,couchbase/perfrunner,hsharsha/perfrunner,mikewied/perfrunner,hsharsha/perfrunner,vmx/perfrunner,pavel-paulau/perfrunner,couchbase/perfrunner,thomas-couchbase/perfrunner,pavel-paulau/perfrunner,mikewied/perfrunner,EricACooper/perfrunner,pavel-paulau/perfrunner,couchbase/perfrunner,PaintScratcher/perfrunner,EricACooper/perfrunner,vmx/perfrunner,dkao-cb/perfrunner,pavel-paulau/perfrunner,PaintScratcher/perfrunner,couchbase/perfrunner,thomas-couchbase/perfrunner,couchbase/perfrunner,EricACooper/perfrunner,couchbase/perfrunner