Since commit f071b0f4, we ignore command line
arguments so there's no way to use --version. Given the "__version__" variable
and the "version" OptionParser keyword argument are only used to
support --version, let's remove all this.

Besides, we failed to update that version number so even if it was
working, --version would always output a wrong value.

Note that __version__ might make sense in a module (PEP 396, deferred)
but this program is not a module.