/mandos/release

Require Python 2.7.

This is in preparation for the eventual move to Python 3, which will
happen as soon as all Python modules required by Mandos are available.
The mandos-ctl and mandos-monitor programs are already portable
between Python 2.6 and Python 3 without changes; this change will
bring the requirement up to Python 2.7.

* INSTALL (Prerequisites/Libraries/Mandos Server): Document
                                                   requirement of
                                                   Python 2.7; remove
                                                   Python-argparse
                                                   which is in the
                                                   Python 2.7 standard
                                                   library.
* debian/control (Source: mandos/Build-Depends-Indep): Depend on
                                                       exactly the
                                                       python2.7
                                                       package and all
                                                       the Python 2.7
                                                       versions of the
                                                       python modules.
  (Package: mandos/Depends): - '' - but still depend on python (<=2.7)
                            and the generic versions of the Python
                            modules; this is for mandos-ctl and
                            mandos-monitor, both of which are
                            compatible with Python 3, and use
                            #!/usr/bin/python.
* mandos: Use #!/usr/bin/python2.7 instead of #!/usr/bin/python.