pgsql: Replace pg_class.relhasexclusion with pg_index.indisexclusion.

Replace pg_class.relhasexclusion with pg_index.indisexclusion.

There isn't any need to track this state on a table-wide basis, and trying
to do so introduces undesirable semantic fuzziness. Move the flag to
pg_index, where it clearly describes just a single index and can be
immutable after index creation.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=bd1ad1b019cda851a3e925133c056930368e6424

Modified Files
--------------
doc/src/sgml/catalogs.sgml | 26 +++++++++++---------------
src/backend/catalog/heap.c | 1 -
src/backend/catalog/index.c | 31 ++++++++++---------------------
src/backend/commands/vacuum.c | 17 ++++-------------
src/backend/parser/parse_utilcmd.c | 4 ++--
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_class.h | 24 +++++++++++-------------
src/include/catalog/pg_index.h | 24 +++++++++++++-----------
8 files changed, 52 insertions(+), 77 deletions(-)