Manual update for --continue option

Manual update for --continue option

Patch adds to mdadm man the following information:

--freeze-reshape
  Option  is  intended  to  be used in start-up scripts during initrd boot
  phase.  When array under reshape is assembled during initrd phase,
  this option stops reshape after reshape critical section is being
  restored. This happens before file system pivot operation and avoids lost
  of file system context.  Loosing file system context would cause
  reshape to be broken.

  Reshape can be continued later using -continue option for grow command.

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