CORBA3 — discussion on the create_union_tc operation could use some clarifications

The discussion on the create_union_tc operation could use some clarifications to prevent implementation errors.

Firstly, in the previous paragraph of the spec it states that member names must be unique, but this is not true for unions: only the member (label) values need to be unique, not the member names.

Secondly, there is a check that each member (label) type matches the discriminator type, but this will not hold for the default label, because according to the typecode spec (section 4.11.1) the default label type of a union will be octet so it will never match the discriminator type.

There is indeed a defect that should be fixed by replacing a single sentence as shown below