pgsql: Add new catalog called pg_init_privs

Add new catalog called pg_init_privs

This new catalog holds the privileges which the system was
initialized with at initdb time, along with any permissions set
by extensions at CREATE EXTENSION time. This allows pg_dump
(and any other similar use-cases) to detect when the privileges
set on initdb-created or extension-created objects have been
changed from what they were set to at initdb/extension-creation
time and handle those changes appropriately.

Reviews by Alexander Korotkov, Jose Luis Tallon

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/6c268df1276e9dd73e4d2cc89cf8787e8f186bda

Modified Files
--------------
doc/src/sgml/catalogs.sgml | 108 +++++++++++++++++++++
src/backend/catalog/Makefile | 2 +-
src/backend/catalog/aclchk.c | 149 +++++++++++++++++++++++++++++
src/backend/catalog/dependency.c | 46 ++++++++-
src/bin/initdb/initdb.c | 143 +++++++++++++++++++++++++++
src/include/catalog/indexing.h | 3 +
src/include/catalog/pg_init_privs.h | 101 +++++++++++++++++++
src/test/regress/expected/sanity_check.out | 1 +
8 files changed, 549 insertions(+), 4 deletions(-)