pgsql: ALTER TABLE OWNER must change the ownership of the table's

Log Message:
-----------
ALTER TABLE OWNER must change the ownership of the table's rowtype too.
This was not especially critical before, but it is now that we track
ownership dependencies --- the dependency for the rowtype *must* shift
to the new owner.  Spotted by Bernd Helmle.
Also fix a problem introduced by recent change to allow non-superusers
to do ALTER OWNER in some cases: if the table had a toast table, ALTER
OWNER failed *even for superusers*, because the test being applied would
conclude that the new would-be owner had no create rights on pg_toast.
A side-effect of the fix is to disallow changing the ownership of indexes
or toast tables separately from their parent table, which seems a good
idea on the whole.

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        alter_table.sgml (r1.78 -> r1.79)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_table.sgml.diff?r1=1.78&r2=1.79)
    pgsql/src/backend/commands:
        tablecmds.c (r1.165 -> r1.166)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/tablecmds.c.diff?r1=1.165&r2=1.166)
        typecmds.c (r1.77 -> r1.78)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/typecmds.c.diff?r1=1.77&r2=1.78)
    pgsql/src/include/commands:
        typecmds.h (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/typecmds.h.diff?r1=1.12&r2=1.13)
    pgsql/src/test/regress/expected:
        dependency.out (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/dependency.out.diff?r1=1.1&r2=1.2)
    pgsql/src/test/regress/sql:
        dependency.sql (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/dependency.sql.diff?r1=1.1&r2=1.2)