Make distro_info return an integer for version

Make distro_info task return an integer for os version.

Also fix os version check when checking if should install abrt plugin or
not on the provision_install task.
The intent of this code is explained by the "discover the version" comment, and the mechanics of this code are explained by [the docs](https://docs.python.org/3/library/re.html#re.match.group). Do we still need further comments? This is a very common way of using Python's regular expressions.