FIX: md runs recovery instead reshape for growing single disk raid0 array

FIX: md runs recovery instead reshape for growing single disk raid0 array

Problem occurs when we want to expand single disk raid0 array.
This is done via degraded 2 disks raid4 array. When new spare disk
for reshape is added to array, md immediately initiates recovery before
mdadm can configure and start reshape. This is due fact that 2 disk
raid4/5 array is special md case.
Mdmon does nothing here because container is blocked.
This is caused because after takeover array is not in frozen state in md.

Put array in to frozen state after takeover to allow mdadm to finish
configuration before reshape is executed in md.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>