pgsql: Support ALTER TYPE RENAME.

Log Message:
-----------
Support ALTER TYPE RENAME. Petr Jelinek

Modified Files:
--------------
pgsql/doc/src/sgml/ref:
alter_type.sgml (r1.4 -> r1.5)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_type.sgml?r1=1.4&r2=1.5)
pgsql/src/backend/catalog:
pg_type.c (r1.115 -> r1.116)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/pg_type.c?r1=1.115&r2=1.116)
pgsql/src/backend/commands:
alter.c (r1.27 -> r1.28)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/alter.c?r1=1.27&r2=1.28)
tablecmds.c (r1.242 -> r1.243)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/tablecmds.c?r1=1.242&r2=1.243)
typecmds.c (r1.113 -> r1.114)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/typecmds.c?r1=1.113&r2=1.114)
pgsql/src/backend/parser:
gram.y (r2.607 -> r2.608)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y?r1=2.607&r2=2.608)
pgsql/src/backend/tcop:
utility.c (r1.290 -> r1.291)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/utility.c?r1=1.290&r2=1.291)
pgsql/src/include/catalog:
pg_type.h (r1.191 -> r1.192)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_type.h?r1=1.191&r2=1.192)
pgsql/src/include/commands:
tablecmds.h (r1.37 -> r1.38)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/tablecmds.h?r1=1.37&r2=1.38)
typecmds.h (r1.22 -> r1.23)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/typecmds.h?r1=1.22&r2=1.23)