Changes

jobs/gerrit: osmo-ttcn3-hacks: drop chown

The chown takes some time, do it once when building the docker image
instead of doing it for every gerrit verification run.

Depends: docker-playground Id51885d0929f4966b1a4a181b3453c06d7956b53
Change-Id: I4bea336097e8180b19b3afa41c0b984d93c21bd1