ns: Use ns_ prefix in routines

The routines are not per-task but per namespace rather.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
ns: ipc -- Add warning about ipc conversion.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
ns: ipc -- Add conversion of IPC variables

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
ns: ipc -- Convert SysV messages

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
ns: ipc -- Zeroify pad in write_ns_ipc_sem

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
ns: ipc -- Add stub for SysV shared memory

Strictly speaking it's just a stub for data, there
is something wrong inside the checkpoint file since
even when test definitely has SysV memory, after
resume it get dropped.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>