[bug#30629] Device mapper modalias

[Danny Milosavljevic]

> Also, Linux dm.c lazily modprobes "dm-%s", target_type.

Very similar for raid and other md stuff (see linux/drivers/md/md.c), just with 
modprobe

  "md-level%s", clevel

and

  "md-%s", level

and

  "md-cluster".

Values for these placeholders can be found out by examining the raid superblock.

But I think in the long run it would be nice if the RAID setup itself was in
/etc/config.scm (if it isn't already - dunno).