packaging: Make configure script do all tests each time

This commits adds cleaning cmake's cache each time the ./configure
script is being used, so that it would discover all the configuration
each time the script is being run. Any caching confuses people who are
familiar with configure scripts, because after fixing dependencies and
running ./configure once again they expect everything to work fine.

Change-Id: Id58f3d9c54d3712e5372c214393bc5f65b85ea60