Allow to tear-down a node waiting to be deployed

Introducing a new state, WAITDEPLOYING, those nodes which have failed
to POST and trigger the vendor_passthru._continue_deploy() can be
tear-down.

Closes-Bug: #1270986
Change-Id: Ib98f1ba6a29de46df9ce54941d0558df4f241f40
Merge "Allow to tear-down a node waiting to be deployed"