Microshift will not boot if the host has no internet connection

See https://github.com/redhat-et/microshift/issues/553

What happened:

Booting microshift with ethernet disconnected failed

What you expected to happen:

To boot and services to come up.

How to reproduce it (as minimally and precisely as possible):

Start a system with ethernet link down, try to start microshift.

Anything else we need to know?:

Environment:

• Microshift version (use microshift version):
  MicroShift Version: 4.8.0-0.microshift-2021-11-19-115908-14-g18aff6b
  Base OKD Version: 4.8.0-0.okd-2021-10-10-030117

• Hardware configuration:

• OS (e.g: cat /etc/os-release):

• Kernel (e.g. uname -a):

• Others:

Relevant Logs

ene 11 18:18:37 jetson-tx2.local systemd[1]: Started MicroShift.
ene 11 18:18:37 jetson-tx2.local microshift[7819]: time="2022-01-11T18:18:37+01:00" level=fatal msg="failed to get host IP: no default r
ene 11 18:18:37 jetson-tx2.local systemd[1]: microshift.service: Main process exited, code=exited, status=1/FAILURE
ene 11 18:18:37 jetson-tx2.local systemd[1]: microshift.service: Failed with result 'exit-code'.