CORBA24 — Version and byte order changes when fragmenting messages (interop)

It's occoured to me that according to the spec it's allowable for
a message to be fragmented and have second and subsequent
fragments change the version fields.

Having the version change while in the middle of reading a
wstring could cause problems, the CDR encoding of version 1.1
strings is always two bytes longer than the corresponding 1.2
encoding, if the version changed while in the middle of reading
the wstring the length field would be out by two.

Secondly if request IDs are per-protocol rather than
per-connection (as aired in issue 3438) then the request ids of
the fragments could interfere.

I think an extra phrase should be added to the spec with regards
to fragmentation, similar to the one regarding byte order:

The version of fragments must match the version of the initial message that
the fragment extends.

Close without revision since the spec was already clarified to state this.