Testing FR support in osmo-gbproxy is a bit more complicated
as it involves the "hdlc" net-devices privded by the hdlc_fr.ko
kernel module.
So we need to
* run on a host with actual hdlc net-devices (e.g. dahdi_dyamic_loc)
* move those net-devices into the containers after starting them
* wait for the net-devices to appear in the containers before starting
either gbproxy or the test suite
Change-Id: Id4b52877db53cb6e59f6d0d3f754aaae633949e8
