minijail: bring up loopback interface in new net namespaces

For basic network logic, we need loopback.  Bring it up all the time
in new net namespaces since it shouldn't cause a problem otherwise --
it's not like it gets us external network connectivity.

BUG=chromium:665649
TEST=`sudo ./minijail0 -r -v -p -e /sbin/ip a s` shows loopback as up

Change-Id: I7e98f0ca42a2993e8c8e2b1de96df7b68c21e3f0
1 file changed