We're getting Glance task timeout errors when trying to upload new
images into rax-iad, which seems to be resulting in rapidly leaking
images and may be creating an ever-worsening feedback loop. Let's
pause uploads for now since they're not working anyway, and
hopefully that will allow us to clean up the mess that's been
created more rapidly as well.
Change-Id: I0cc93a80e2cfa2ef761c6f538e134505bf4dc53c
71d1f02164