Bug#839253: (no subject)

[Barry Warsaw]

A couple of small decisions in discussion w/Martin:

* If you have `Tests: foo` and `Features: test-name=bar`, warn and ignore the
  test-name feature.

* If you have multiple test-name features, e.g.
  `Features: test-name=a, test-name=b`
  warn and skip.

* I want the feature name to match the command line option, but inconsistent
  with the other autopkgtest options, we have --testname.  For consistency,
  this should be called --test-name, so let's support --test-name as an alias
  and deprecate --testname, with eventual hiding and/or removal some time
  later.