[debian][network] fixed _run_system_command def; was braced :sleepy:
[debian][network] fixed _run_system_command def; was braced :sleepy:

rackerlabs/openstack-guest-agents-unix,rackerlabs/openstack-guest-agents-unix,joejulian/openstack-guest-agents-unix,joejulian/openstack-guest-agents-unix,rackerlabs/openstack-guest-agents-unix,joejulian/openstack-guest-agents-unix