Merge pull request #253 from aplanas/master

Do not download requests without RPM.
we need to specify the target or the API will do some invalid magic
netto one less failure
Merge pull request #254 from openSUSE/coolo_target_package

Coolo target package
fix python syntax
install virtualbox on the DVD
Merge pull request #255 from aplanas/master

 Implement an external cache for checkrepo
Merge pull request #256 from openSUSE/coolo_fix_python

Coolo fix python
Makes sure that the cache dir is there.