CLOUDSTACK-8897: baremetal:addHost:make host tag info mandtory in baremetal addhost Api call

addhost api is successful with out providing the host tag info and we recommend host tag is mandatory for bare-metal.
In the current implementation host tag check is happening at vm deployment stage but it will be good to have host tag field as mandatory field during adding of the host it self.

Author: Harikrishna Patnala

server/src/com/cloud/resource/ResourceManagerImpl.java

@@ -679,6 +679,13 @@ private List<HostVO> discoverHostsFull(final Long dcId, final Long podId, Long c
             }
         }
 
+        if ((hypervisorType.equalsIgnoreCase(HypervisorType.BareMetal.toString()))) {
+            if (hostTags == null || hostTags.size() == 0) {
+                throw new InvalidParameterValueException("hosttag is mandatory while adding host of type Baremetal");
+            }
+
+        }
+
         if (clusterName != null) {
             final HostPodVO pod = _podDao.findById(podId);
             if (pod == null) {