removed the multiline if condition as it seems unnecessary and also prevents the warning message (#66543)

* removed "this_dns_name" variable comparision with empty string.  #66537

* removed the imultiline if condition as it seems unnecessary.  #66537

contrib/inventory/cobbler.py

@@ -215,8 +215,7 @@ class CobblerInventory(object):
                 for (iname, ivalue) in iteritems(interfaces):
                     if ivalue['management'] or not ivalue['static']:
                         this_dns_name = ivalue.get('dns_name', None)
-                        if this_dns_name is not None and this_dns_name is not "":
-                            dns_name = this_dns_name
+                        dns_name = this_dns_name if this_dns_name else ''
 
             if dns_name == '' or dns_name is None:
                 continue