[ebxml-msg] Issue#23: 3.1.9 MessageHeader example

A Role element has a cardinality of zero or one. It
need not be present in a message, but an MSH MUST
be implemented to process it if present.

My only suggestion for this issue was that the example
be made consistent. Either it is used or it is not.
Having a To/Role and not a From/Role really makes
this whole thing quite confusing. I say make it
balanced.

Cheers,

Chris