pgsql: Tweak BRIN minmax operator class

Tweak BRIN minmax operator class

In the union support proc, we were not checking the hasnulls flag of
value A early enough, so it could be skipped if the "allnulls" flag in
value B is set.  Also, a check on the allnulls flag of value "B" was
redundant, so remove it.

Also change inet_minmax_ops to not be the default opclass for type inet,
as a future inclusion operator class would be more useful and it's
pretty difficult to change default opclass for a datatype later on.
(There is no catversion bump for this catalog change; this shouldn't be
a problem.)

Extracted from a larger patch to add an "inclusion" operator class.

Author: Emre Hasegeli

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/972bf7d6f13005dfe89ae3f8a3b937a4a0580c85

Modified Files
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src/backend/access/brin/brin_minmax.c |   19 ++++++++++---------
src/include/catalog/pg_opclass.h      |    2 +-
src/test/regress/expected/brin.out    |    2 +-
src/test/regress/sql/brin.sql         |    2 +-
4 files changed, 13 insertions(+), 12 deletions(-)