postage stamp dependents get stuck if chip destreaking fails

[bills]

There was a period where camera runs were silently failing to output all of the camera stage mask files. Warp and destreak processing fell back to the chip stage mask in this case. This allowed exposures to go through the system in this state.

Since we no longer allow the fallback updates for runs in this state fail.

These errors are difficult to recognize automatically because they have the same symptom as network outages 'failed to open file blah'

A similar problem is that destreaking fails because the previous run wasn't completely cleaned up. [At some time there was a bug in destreak cleanup that left the chip mask files lying around.]

We need to figure out how to detect these problems and correct them iff possible.

If the problem can't be corrected we need to stop the job and return the proper error code to the client PSTAMP_GONE