pgsql: Get rid of the pg_shdepend entry for a TOAST table; it's

Log Message:
-----------
Get rid of the pg_shdepend entry for a TOAST table; it's unnecessary since
there's an indirect dependency on the owner via the parent table.  We were
already handling indexes that way, but not toast tables for some reason.
Saves a little catalog space and cuts down the verbosity of checkSharedDependencies
reports.

Modified Files:
--------------
    pgsql/src/backend/catalog:
        heap.c (r1.320 -> r1.321)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/heap.c.diff?r1=1.320&r2=1.321)
    pgsql/src/backend/commands:
        tablecmds.c (r1.222 -> r1.223)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/tablecmds.c.diff?r1=1.222&r2=1.223)