Fix name conflicts that prevent down-converting RAID1 when specifying a device

Fix name conflicts that prevent down-converting RAID1 when specifying a device

When down-converting a RAID1 device, it is the last device that is extracted
and removed when the user does not specify a particular device.  However,
when a device is specified (and it is not the last), the device is removed and
the remaining sub-LVs are "shifted down" to fill the hole.  This cause problems
when resuming the LV because if the shifted devices were resumed (and thus
renamed) before the sub-LV being extracted, there would be a name conflict.
The solution is to resume the extracted sub-LVs first so that they can be
properly renamed preventing a possible conflict.

This addresses bug 801967.