During the Zed PTG it was decided to handle unsupported features in
Neutron as experimental. See section titled "When we say something is
not supported?", day 2 in . The agreement was:
"We keep existing jobs for linuxbridge driver for example, but when the
tests start to fail we skip them and finally we stop the job also.
To make it clear for operators we add warning logs highlighting that the
given feature/driver is experimental, and introduce cfg option to enable
such features explicitly."
This commit implements this agreement, initially with Linuxbridge