pgsql: Prevent pg_dump from dumping the comment (if any) on the 'public'

Log Message:
-----------
Prevent pg_dump from dumping the comment (if any) on the 'public' schema.
This is to avoid uselessly requiring superuser permissions to restore
the dump without errors.  Pretty grotty, but no better alternative seems
available, at least not in the near term.

Modified Files:
--------------
    pgsql/src/bin/pg_dump:
        pg_backup_archiver.c (r1.151 -> r1.152)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c?r1=1.151&r2=1.152)