revert snapshotting for now

There is a bug in Warden that causes it to leave unreferenced containers
around. Having them cleared on Warden startup is a band-aid for now, so
we can't do snapshot deploys.

[#57361124 #62709652]

Revert "fix dea drain script"

This reverts commit c06d9e59c8fb1e751955057434015797f46d0611.

Revert "update drain script to add snapshotting"

This reverts commit b9aafcb775be7e140542ee587eb6579c26ff41f0.

Revert "warden: don't destroy containers on startup"

This reverts commit 9065ec60819476e4d30699273fe2cb12294f8d6b.
Merge git://github.com/cloudfoundry/cf-release