Add fchmod() stub

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Add fchown() stub

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Add F_SETLK, F_GETLK stub on fcntl

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>