Fix mounting of repositories in gerrit-slave chart

The directory containing the repositories was not symlinked correctly
in the gerrit-slave chart, if the test mode was not used.

Now the `/var/gerrit/git`-directory is deleted after the default site is
initialized, allowing the symlinking of the persisted volume.

Change-Id: If52a0e528fee117cc65fbbd229ecb297d718d6ba
diff --git a/helm-charts/gerrit-slave/templates/gerrit-slave.deployment.yaml b/helm-charts/gerrit-slave/templates/gerrit-slave.deployment.yaml
index 759ef2a..68cfed3 100644
--- a/helm-charts/gerrit-slave/templates/gerrit-slave.deployment.yaml
+++ b/helm-charts/gerrit-slave/templates/gerrit-slave.deployment.yaml
@@ -60,6 +60,9 @@
           /var/tools/gerrit_init.py \
             -s /var/gerrit \
             -p singleusergroup
+
+          # The git repositories will be mounted from a volume
+          [ -L /var/gerrit/git ] || rm -rf /var/gerrit/git
         volumeMounts:
         - name: gerrit-site
           mountPath: "/var/gerrit"