minijail: Add option to enter a new IPC namespace

Export this feature through the '-l' option to minijail0.

TEST=run minijail0 with the -l option, check that the executed program
is in a different ipc namesspace with /proc/self/ns/ipc.
BUG=b/25770648

Change-Id: Ia8f72cc59160fc736c8a58cb68d9894f9c92281c
Signed-off-by: Dylan Reid <dgreid@chromium.org>
4 files changed