[PATCH] fix rescan_partitions to return errors properly

The only error code which comes from the partition checkers is -1, when
they finds an EIO.  As per the discussion, ENOMEM values were ignored,
as they might scare the users.

So, with the current code, we end up returning -1 and not EIO for the
ioctl() calls.  Which doesn't give any clue to the user of what went
wrong.

Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>