[PATCH] md: make 'md' and alias for 'md-mod'

Until the bitmap code was added,

   modprobe md

would load the md module.  But now the md module is called 'md-mod', so we
really need an alias for backwards comparability.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>