ilure can be tested with relative lseek, we have to trust
kernel that on success we've got right file offset.  With this fix in
place I have finally real core files instead of 1KB fragments...

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
[ Cleaned it up a bit while here - use SEEK_CUR instead of hardcoding 1 ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>