Return groupBy hypervisor type when listing clusters by zone id

Author: slavkap

engine/schema/src/main/java/com/cloud/dc/dao/ClusterDaoImpl.java

@@ -81,6 +81,7 @@ public ClusterDaoImpl() {
 
         ZoneSearch = createSearchBuilder();
         ZoneSearch.and("dataCenterId", ZoneSearch.entity().getDataCenterId(), SearchCriteria.Op.EQ);
+        ZoneSearch.groupBy(ZoneSearch.entity().getHypervisorType());
         ZoneSearch.done();
 
         AvailHyperSearch = createSearchBuilder();