pgsql: Fix ancient get_object_address_opf_member bug

Fix ancient get_object_address_opf_member bug

The original coding was trying to use a TypeName as a string Value,
which doesn't work; an oversight in my commit a61fd533. Repair.

Also, make sure we cover the broken case in the relevant test script.

Backpatch to 9.5.

Discussion: https://postgr.es/m/20170315151829.bhxsvrp75xdxhm3n@alvherre.pgsql

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/a3eac988c26706059ae74c740a1abcb588449abe

Modified Files
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src/backend/catalog/objectaddress.c | 18 +++++++++++-------
src/test/regress/expected/object_address.out | 9 +++++++++
src/test/regress/sql/object_address.sql | 6 ++++++
3 files changed, 26 insertions(+), 7 deletions(-)