By default, passt itself attaches to the first host interface with a
default route. However, when determining the host interface name the tests
implicitly select the *last* host interface: they use a jq expression which
will list all interfaces with default routes, but the way output detection
works in the scripts, it will only pick up the last line.
If there are multiple interfaces with default routes on the host, and they
each have a different address, this can cause spurious test failures.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
3eaf9f5320