pgsql: Remove pg_class.relhaspkey

Remove pg_class.relhaspkey

It is not used for anything internally, and it cannot be relied on for
external uses, so it can just be removed.  To correct recommended way to
check for a primary key is in pg_index.

Discussion: https://www.postgresql.org/message-id/flat/b1a24c6c-6913-f89c-674e-0704f0ed69db@2ndquadrant.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f66e8bf875f691db4c5d0173fc39b5a9c3ec969c

Modified Files
--------------
doc/src/sgml/catalogs.sgml          |  9 ---------
src/backend/catalog/heap.c          |  1 -
src/backend/catalog/index.c         | 32 ++-----------------------------
src/backend/commands/vacuum.c       | 10 ----------
src/backend/rewrite/rewriteDefine.c |  1 -
src/include/catalog/catversion.h    |  2 +-
src/include/catalog/pg_class.h      | 38 ++++++++++++++++++-------------------
7 files changed, 21 insertions(+), 72 deletions(-)