reduce OS release distinction in crypto to majors

only do major releases as the subversions inside a major stay the same. the only exception here is ubuntu, which changes from 12.04 to 12.10 and 14.04 to 14.10. The supported set still works perfectly between these.

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
Merge pull request #22 from TelekomLabs/simplify-crypto

reduce OS release distinction in crypto to majors