Changes

…gerrit/comment_generate: make error more helpful

The start of a stage may also not be found if the related -build job was
not deployed. This was not obvious before, add a hint to the error
message.

Change-Id: Iec5f4cde53b763bb6c814934abcc83e39518566f

jobs/osmo-gsm-tester-build: fix Missing parameter

Use OSMO_GSM_TESTER_BRANCH as shell variable ('$...'), not as jenkins
job builder parameter (${...}). This is how we do it in other jobs as
well, e.g. jobs/osmocom-obs.yml.

Apparently the workaround in the file happened to work earlier, but it
does not work anymore with Jenkins Job Builder version 6.3.0. Remove it.

Fix for:
  osmo-gsm-tester-builder.yml:119:15: While formatting string '${OSMO_GSM_TESTER_BRANCH}': Missing parameter: 'OSMO_GSM_TESTER_BRANCH'
                - ${OSMO_GSM_TESTER_BRANCH}
                  ^

Change-Id: I3b6b16964a4d8a51fd3ecc0d670805182a8c6586

libosmo-sccp -> libosmo-sigtran

Adjust to:
* libosmo-sccp.git has been renamed to libosmo-sigtran.git
* libosmo-sccp static libraries have been split into
  libosmo-sccp-legacy.git

build-old-tags-against-master: libosmo-sccp is intentionally kept in
  REPOS_TAGS, so old libosmo-sccp versions are built against current
  master of Osmocom libraries.

Related: OS#6239
Change-Id: I509b1cc2a5260c82ef32e9543513110949311188

OBS: add libosmo-sccp-legacy URL

Change-Id: Ibacb7e39525f679914ad6add8aa21fce59ca3e5d

ansible: update rpi4-2 and rpi4-3

Adjust SSH key and hostname after both have been reinstalled with 64bit
raspbian 12.

Related: OS#6549
Change-Id: I959a564bb597f433012a14ce56da4865d3392170