bdremove: Fix the sysfs device properties

The remove sys file for removing a device was write-only, but only
the read function was filled in, probably due to a faulty forward
port.  Do a write function instead.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
bdremove: Rework finding filesystems mounted on a device

The code to find the filesystems mounted on a device was wrong.  Rewrite
it to use the existing structures that do this instead of creating new
ones.

Signed-off-by: Corey Minyard <cminyard@mvista.com>