Make ip_address read only

Setting a different value for ip_address
and hostname does not work with the current
way we create receptor certs.

awx/api/views/__init__.py

@@ -343,6 +343,7 @@ class InstanceDetail(RetrieveUpdateAPIView):
         # these fields are only valid on creation of an instance, so they unwanted on detail view
         data.pop('node_type', None)
         data.pop('hostname', None)
+        data.pop('ip_address', None)
         return super(InstanceDetail, self).update_raw_data(data)
 
     def update(self, request, *args, **kwargs):