[PATCH] device-mapper: list_versions fix

In some circumstances the LIST_VERSIONS output is truncated because the size
calculation forgets about a 'uint32_t' in each structure - but the inclusion
of the whole of ALIGN_MASK frequently compensates for the omission.

This is a quick workaround to use an upper bound.  (The code ought to be fixed
to supply the actual size.)

Running 'dmsetup targets' may demonstrate the problem: when I run it, the last
line comes out as 'erro' instead of 'error'.  Consequently, 'lvcreate --type
error' doesn't work.

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>