swc-installation-test-2.py: Cache check errors
swc-installation-test-2.py: Cache check errors

Avoid running the same check (e.g. 'python') over and over.

selimnairb/2014-02-25-swctest,selimnairb/2014-02-25-swctest,selimnairb/2014-02-25-swctest,selimnairb/2014-02-25-swctest,selimnairb/2014-02-25-swctest,selimnairb/2014-02-25-swctest