jobs/gerrit-binpkgs: don't use multiple-scm plugin

Change the default branch from origin/master to master, as the git clone
command expects just the branch name without a remote name.

Related: OS#5763
Change-Id: Ia5a17c6d25bf811a992ab495a2531ae613cb144f

jobs/gerrit-binpkgs.yml

@@ -33,7 +33,7 @@
           name: BRANCH_CI
           description: |
                 osmo-ci.git branch
-          default: 'origin/master'
+          default: 'master'
       - string:
           name: GERRIT_REPO_URL
           description: set by gerrit verification pipeline job
@@ -61,13 +61,6 @@
          skip-tag: true
          submodule:
            recursive: false
-      - git:
-         basedir: 'osmo-ci'
-         url: 'https://gerrit.osmocom.org/osmo-ci'
-         credentials-id: d5eda5e9-b59d-44ba-88d2-43473cb6e42d
-         branches:
-           - '$BRANCH_CI'
-         wipe-workspace: true
 
     builders:
       - shell: |-
@@ -80,6 +73,15 @@
             exit 0
           fi
 
+          # Clone osmo-ci.git
+          rm -rf osmo-ci
+          git clone \
+            --depth=1 \
+            --branch="$BRANCH_CI" \
+            https://gerrit.osmocom.org/osmo-ci \
+            osmo-ci
+          git -C osmo-ci log --oneline
+
           # Get distro from type
           case "{type}" in
           deb) distro="debian:11" ;;