Test BuildBot tag push with ssh host key checking disabled

buildbot/buildbot_steps.sh

@@ -175,7 +175,7 @@ function tag_head_and_push() {
     fi
 
     git tag -a "g_$(git rev-parse HEAD)" HEAD -m "BuildBot: tag commit for release $(git rev-parse HEAD)" || return 2
-    git push --tags origin master
+    env GIT_SSH_COMMAND="ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no" git push --tags origin master
     if [ $? -ne 0 ]; then
         >&2 echo 'Error during attempted git push of new tag'
         return 3