RAID: Make 'lvchange --refresh' restore transiently failed RAID PVs

RAID:  Make 'lvchange --refresh' restore transiently failed RAID PVs

A new function (dm_tree_node_force_identical_table_reload) was added to
avoid the suppression of identical table reloads.  This allows RAID LVs
to reload the on-disk superblock information that contains which devices
have failed and the bitmaps.  If the failed device has returned, this has
the effect of restoring the device and initiating recovery.  Without this
patch, the user had to completely deactivate their RAID LV and re-activate
it in order to restore the failed device.  Now they simply need to
suspend and resume (which is done by 'lvchange --refresh').

The identical table suppression is only avoided if the LV is not PARTAIL
(i.e. all of it's devices can be seen and read by LVM) and the kernel
status of the array contains failed devices.  In other words, the function
will only be called in the case where we may have success in restoring
a failed device in the array.