vzctl snapshot-list -o device: fix width

Fix formatting when printing device field in vzctl snapshot-list.

Obviously, since we use 16 characters for a header, we should use
same 16 characters for the value, not 32.

Before this patch, it looks something like this:

 # vzctl snapshot-list 1041 -o current,device,current
 C DEVICE           C
 *                                  *

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
1 file changed