OK, that's my f*ckup in rd.c (not on initrd path, actually) + couple of
f*ckups from Pat (mine: forgot to bump ->bd_count in rd_open(), Pat's:
dropped reference to gendisk on del_gendisk(), resulting in use of
kfree'd object + tried to remove a symlink that didn't exit).

This fixes these.  It also changes order of blkdev_put()/del_gendisk()
in initrd_release() - better safe than sorry.

It got initrd working on my boxen...