Merge remote-tracking branch 'ansgar/pu/multiarchive-2'

* ansgar/pu/multiarchive-2:
  daklib/archive.py: use target suite as source_suite when installing to build queues
  daklib/archive.py: doc: only subqueries are accepted
  daklib/archive.py: use only enhanced suites as default source_suites
  don't send mails about accepted buildd uploads to maintainer
  dak/process_upload.py: include full changes file with signature

Signed-off-by: Joerg Jaspert <joerg@debian.org>