Use the correct types when calling FS_IOC_GETFLAGS/FS_IOC_SETFLAGS.

Despite the definitions in <linux/fs.h> these ioctls take int
arguments, not longs. This is important for 64-bit big endian
machines.

See http://marc.info/?l=linux-fsdevel&m=138552482917220&w=2

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
[rlb@defaultvalue.org: adjust commit message; use "I" conversion
 to/from Python instead of "k".]
Signed-off-by: Rob Browning <rlb@defaultvalue.org>