pgsql: Make relhasrules and relhastriggers work like relhasindex, namely

Log Message:
-----------
Make relhasrules and relhastriggers work like relhasindex, namely we let
VACUUM reset them to false rather than trying to clean 'em up during DROP.

Modified Files:
--------------
pgsql/doc/src/sgml:
catalogs.sgml (r2.181 -> r2.182)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/catalogs.sgml?r1=2.181&r2=2.182)
pgsql/src/backend/commands:
analyze.c (r1.127 -> r1.128)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/analyze.c?r1=1.127&r2=1.128)
vacuum.c (r1.379 -> r1.380)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/vacuum.c?r1=1.379&r2=1.380)
vacuumlazy.c (r1.109 -> r1.110)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/vacuumlazy.c?r1=1.109&r2=1.110)
pgsql/src/backend/rewrite:
rewriteRemove.c (r1.73 -> r1.74)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteRemove.c?r1=1.73&r2=1.74)
pgsql/src/backend/utils/cache:
relcache.c (r1.275 -> r1.276)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/relcache.c?r1=1.275&r2=1.276)
pgsql/src/include/commands:
vacuum.h (r1.80 -> r1.81)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/vacuum.h?r1=1.80&r2=1.81)