Fix deployment growth issues

[Others]

The subtle bug is the following:

Timmy deploys a component from his repo timmysGreatComponent
Timmy pushes a commit to his dev branch
The deployment manager sees it should deploy (since there is a new push event)
There are now two workers running identical versions of the component
This situation remains until there is a push to master
(so we could end up with timmy's component on every worker)
I think this means we need to be cleverer about push events -- make sure they come from the right branch or stop using the HEAD trick. We also could just clean up this situation in the auto scaling stack, but that seems inelegant.