Bump WX_CURRENT back to 3, this must stay the same as

Bump WX_CURRENT back to 3, this must stay the same as
wx_release_number until bakefile is fixed to unlink the
the soversion from it.  Ideally of course it should track
binary incompatible releases instead.

Update the Debian scripts to suit the new site-packages
location for wxPython.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@30489 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775