pgsql: Remove ill-considered (not to mention undocumented) attempt to

Log Message:
-----------
Remove ill-considered (not to mention undocumented) attempt to make
contrib/intarray's GIN opclass override the built-in default.  Per bug #3048
and other complaints.

Modified Files:
--------------
    pgsql/contrib/intarray:
        README.intarray (r1.13 -> r1.14)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/README.intarray?r1=1.13&r2=1.14)
        _int.sql.in (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int.sql.in?r1=1.23&r2=1.24)
        uninstall__int.sql (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/uninstall__int.sql?r1=1.5&r2=1.6)
    pgsql/contrib/intarray/expected:
        _int.out (r1.18 -> r1.19)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/expected/_int.out?r1=1.18&r2=1.19)
    pgsql/contrib/intarray/sql:
        _int.sql (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/sql/_int.sql?r1=1.10&r2=1.11)