fix wendelin/software.cfg and do some clean up

after https://lab.nexedi.com/nexedi/slapos/-/commit/cc44b2604b0bf25f580fec1208c1f7eeed4fa56b,

scipy has 2 buildout files: buildout.cfg, python2.cfg

software/erp5/software.cfg has already included the correct version

but in wendelin/software.cfg we still include scipy/buildout.cfg, it seems not correct anymore, so let's remove it

and also do some clean up, the scipy and astor seems already include in stack/erp5

@Tyagov can you please check ? thx