Changes

update osmo-stp.cfg to make STP_Tests work at all again

This syncs osmo-stp.cfg with changes introduced to docker-playground
in Change-Id I210b7d62845075dcfe147f2f77603625cc1e64f9 on March 4th.

I'm really getting tired at fixing up those kind of issues. It's
well-known that config changes must be made first here and then in
docker-playground.

Change-Id: I7f0cef55a9a54f1cc4b23df781dab2afd52aae78