FIX: Unfreeze array on success only

FIX: Unfreeze array on success only

Unfreeze array on success only.
rv is initialized by restart variable so we have 2 cases.
1. regular reshape start
	rv == restart == 0
   this means that real error (returned by reshape) can cause leaving container frozen
   If array is not touched by reshape it can be unfrozen
2. During reshape restart even untouched array under reshape is left unfrozen,
   If reshape is started do not unfreeze array on error also.

This allows user for array repair action
(mdmon will not change array state).

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