Mark "test_subport_connectivity_soft_reboot" as unstable

This issue is related to:
* https://bugs.launchpad.net/neutron/+bug/2033887: the patches
  previously merged in the Neutron repository [1][2] should be
  reverted.
* https://bugs.launchpad.net/neutron/+bug/2024160: this issue
  is still present.

[1]https://review.opendev.org/c/openstack/neutron/+/882581
[2]https://review.opendev.org/c/openstack/neutron/+/888776

Change-Id: I9d8d76810d15913c29610464ab1b8fa34863aaf6
Related-Bug: #2024160
Related-Bug: #2033887
1 file changed