SOAP binding: clarify that the lack {soap mep} value is an error

In Table 5-4. Mapping from XML Representation to SOAP Operation
Component Properties from 5.8.4 Mapping from XML Representation to
Component Properties in Part 2, we say:

   ┌───────────────┬───────────────────────────────────────────────────────┐
   │   Property    │                         Value                         │
   ├───────────────┼───────────────────────────────────────────────────────┤
   │               │ The actual value of the wsoap:mep attribute           │
   │               │ information item, if present. If not, the actual      │
   │               │ value of the wsoap:mepDefault attribute information   │
   │ {soap mep}    │ item of the parent wsdl:binding element information   │
   │               │ item, if present. If not the value as defined by the  │
   │               │ default SOAP binding rules (for SOAP 1.2, see 5.11.3  │
   │               │ Default Binding Rules), if applicable.                │
   ├───────────────┼───────────────────────────────────────────────────────┤

We should add "Otherwise an error" to clarify that it's not OK for
{soap mep} not to have a value.

-- 
Hugo Haas - W3C
mailto:hugo@w3.org - http://www.w3.org/People/Hugo/