pgsql: Move pg_upgrade shared library out into its own /contrib

Log Message:
-----------
Move pg_upgrade shared library out into its own /contrib directory
(pg_upgrade_support).

Modified Files:
--------------
pgsql/contrib:
Makefile (r1.91 -> r1.92)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/Makefile?r1=1.91&r2=1.92)
pgsql/contrib/pg_upgrade:
Makefile (r1.2 -> r1.3)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/Makefile?r1=1.2&r2=1.3)
check.c (r1.1 -> r1.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/check.c?r1=1.1&r2=1.2)
function.c (r1.1 -> r1.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/function.c?r1=1.1&r2=1.2)
pgsql/doc/src/sgml:
pgupgrade.sgml (r1.1 -> r1.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pgupgrade.sgml?r1=1.1&r2=1.2)

Added Files:
-----------
pgsql/contrib/pg_upgrade_support:
Makefile (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade_support/Makefile?rev=1.1&content-type=text/x-cvsweb-markup)
pg_upgrade_support.c (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade_support/pg_upgrade_support.c?rev=1.1&content-type=text/x-cvsweb-markup)

Removed Files:
-------------
pgsql/contrib/pg_upgrade:
pg_upgrade_sysoids.c
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_upgrade/pg_upgrade_sysoids.c)