dm raid: fix use of wrong status char during resynchronization

During a resynchronization, device status char 'a' is output on the raid
status line for every device of a RAID set.  It changes from 'a' to 'A'
(unless device failure) when the resynchronization completes.

Interrupting and restarting a resynchronization, by reloading the DM
table, erroneously lead to status char 'A'.

Fix this by avoiding setting the MD_RECOVERY_REQUESTED flag in
raid_preresume().

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>