python-*-dbg packages should not be stripped

[Matthias Klose <doko@debian.org>]

The packages built for the Python debug interpreters should not be stripped.
Usually this has to be done on a per package basis, however when converting to
the pybuild system, this is easily missed. It is now documented in [1], but I
assume a lot of packages just strip the -dbg packages. Maybe lintian should warn
about python -dbg package,

 - when the extension for the debug interpreter is stripped.
 - when the -dbg package doesn't contain the debug information
   for the normal extension build.

[1] https://wiki.debian.org/Python/LibraryStyleGuide#Building_python_-dbg_packages