In the new _vg_read_for_update(), we always do the check for CLUSTERED vg

In the new _vg_read_for_update(), we always do the check for CLUSTERED vg
status flag after reading the volume group.  Thus, no need to set the flag
in vg_read() or clear it later before calling _vg_bad_status_bits().

Also, add back in the !lockingfailed() as part of the CLUSTERED flag check.
It's unclear why it was removed when the check was moved from
_vg_bad_status_bits() to inside _vg_lock_and_read().
There was an open question about the last check in the 'if' stmt for
lockingfailed() with a previous patch submitted.  However, I would
defer that right now as it is a separate item and this patch should
be no functional change by including the !lockingfailed().

Petr acked this patch on 5/26 I just forgot to check it in.

Acked-by: Petr Rockai <prockai@redhat.com>