Description of problem:
   Web service model , create operation model does not allow to create operations without input or output. Indeed it's possible to ignore warning messages and create the operation anyway. In that case wizard puts nameless and typeless messages in the schema and requires removing messages from the schema with an alternate editor.  

Version-Release number of selected component (if applicable):
 
   TD 9.0.3.Finalv2015

How reproducible:
   Try to create a new operation in web service model 

Steps to Reproduce:
1. Pick one the interfaces that you have in wsdl
2. Create a new operation, give it a name
3. Try to get rid of input message, remove it's name and create 


Actual results:
  Malformed view schema 

Expected results:
  create the operation without the undesired message type 

Additional info: