pgsql: Add btree and hash opclasses for pg_lsn.

Add btree and hash opclasses for pg_lsn.

This is needed to allow ORDER BY, DISTINCT, etc to work as expected for
pg_lsn values.

We had previously decided to put this off for 9.5, but in view of commit
eeca4cd35e284c72b2ea1b4494e64e7738896e81 there's no reason to avoid a
catversion bump for 9.4beta2, and this does make a pretty significant
usability difference for pg_lsn.

Michael Paquier, with fixes from Andres Freund and Tom Lane

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/4c8ab1b91d2bd154031f7bc8529b9e6e2f1cc443

Modified Files
--------------
src/backend/utils/adt/pg_lsn.c       |   28 +++++++-
src/include/catalog/catversion.h     |    2 +-
src/include/catalog/pg_amop.h        |   12 ++++
src/include/catalog/pg_amproc.h      |    2 +
src/include/catalog/pg_opclass.h     |    2 +
src/include/catalog/pg_operator.h    |    2 +-
src/include/catalog/pg_opfamily.h    |    2 +
src/include/catalog/pg_proc.h        |    4 ++
src/include/utils/pg_lsn.h           |    2 +
src/test/regress/expected/pg_lsn.out |  130 ++++++++++++++++++++++++++++++++++
src/test/regress/sql/pg_lsn.sql      |   14 ++++
11 files changed, 196 insertions(+), 4 deletions(-)