[PATCH] device-mapper log bitset: fix big endian find_next_zero_bit

This is a fix to the device-mapper-log-bitset-fix-endian patch that
switched to ext2_* versions of the set and clear bit functions.  The
find_next_zero_bit function also has to be the ext2 one.  Otherwise the
mirror target tries to recover non-existent regions beyond the end of
device.

Signed-off-by: Stefan Bader <shbader@de.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>