WIP: Fixing undeploy of services/stack

@mikesir , I started this branch today because I've noticed recently that stacks are not always being spun down despite their tickets being closed and associated branches being merged. Needless to say, I wasn't able to reproduce that when I actually looked into it. Ha, actually the opposite: I found that stacks were being eagerly spun down despite some of their counterpart services still having non-master source-branches. So I'm a little confused, but here's an initial set of commits.

Going forward, I was hoping to find a way to test my changes before merging them into the current update-stack branch. Any suggestions? The best way I can think of is to add a small script to the normal update-stack pipeline that toggles between the real update-stack.sh and a development branch's update-stack.sh. This could allow the qa pipeline to continue unhindered by normal branches, but then special branches in other repos could trigger the development update-stack.sh script by setting an additional variable like variables[UPDATE-STACK-BRANCH]=update-stack-dev or something like that. Just a guess. Maybe we can talk Monday.