Avoid redefinition of test

test_add_member() is defined twice under the same
name, however checking for different things. Rename
the 2nd instance to _unauthorized to avoid overwriting
the first implementation.

The first check is actually duplicate to test_add_member_positive.
So merging the first check with test_add_member_positive.

Change-Id: Ifb029d8f34f9f4139557bb9b197492fb344a598e
Merge "Avoid redefinition of test"