UI jumps when opening delete modal

[cpx86]

When you open the delete modal, the UI jumps ~15px to the side. This is because we are centering the body horizontally, and when the modal opens, the page width changes. This is due to a bug in Bootstrap's modal component. See twbs/bootstrap#9855

We have a few options for solving this:

1. Don't center the UI
2. Add a CSS hack that's good enough for us
3. Wait for Bootstrap 3.2