Required deb.* properties are not being set when publishing debs

This happens because the .orig file is shared between multiple Debian revisions, which then causes the publisher to incorrectly try to update properties on all the files associated with an old revision of which only the .orig is still published, which results in:

Traceback (most recent call last):
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/services/scripts/base.py", line 95, in log_unhandled_exceptions_func
    return func(self, *args, **kw)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/services/scripts/base.py", line 373, in lock_and_run
    self.run(use_web_security=use_web_security, isolation=isolation)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/services/scripts/base.py", line 95, in log_unhandled_exceptions_func
    return func(self, *args, **kw)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/services/scripts/base.py", line 323, in run
    self.main()
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/scripts/publishdistro.py", line 505, in main
    archive_id, reset_store=reset_store_between_archives
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/scripts/publishdistro.py", line 472, in processArchive
    self.publishArchive(archive, publisher)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/scripts/publishdistro.py", line 429, in publishArchive
    publisher.C_updateArtifactoryProperties(careful_indexing)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/publishing.py", line 847, in C_updateArtifactoryProperties
    old_properties=properties,
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/artifactory.py", line 563, in updateProperties
    entry.updateProperties(publications, old_properties=old_properties)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/lib/lp/archivepublisher/artifactory.py", line 407, in updateProperties
    properties_to_remove, recursive=False
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/env/lib/python3.5/site-packages/artifactory.py", line 1827, in del_properties
    return self._accessor.del_properties(self, properties, recursive)
  File "/srv/launchpad.net/production/launchpad-rev-31c78762a8046acf7ab47372e5d588ebb3759d2e/env/lib/python3.5/site-packages/artifactory.py", line 1167, in del_properties
    raise OSError(2, "No such file or directory: '%s'" % url)
FileNotFoundError: [Errno 2] No such file or directory: '[redacted]/pool/b/bind9/bind9_9.16.1-0ubuntu2.10.debian.tar.xz'

As a result, none of the work that the publisher would have done after that happens, which causes properties to be missing from a bunch of other files.

I have work in progress to fix this by skip...