CLOUDSTACK-5587, CLOUDSTACK-5589: Router version in 2.2.x routers is null. Added null check when comparing min version

server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java

@@ -4074,6 +4074,9 @@ public class VirtualNetworkApplianceManagerImpl extends ManagerBase implements V
     //Checks if the router is at the required version
     // Compares MS version and router version
     private boolean checkRouterVersion(VirtualRouter router){
+        if(router.getTemplateVersion() == null){
+            return false;
+        }
         String trimmedVersion = Version.trimRouterVersion(router.getTemplateVersion());
         return (Version.compare(trimmedVersion, _minVRVersion) >= 0);
     }