Snort version generator/detector logic broken

[puck]

As noted in #60, the logic to convert the installed Snort version to a version of the rules to download is insufficient. If Snort is version 3.7.3.0, then the version to download is 3.7.0.0.

I don't know if this is predictable, or maybe the Snort project needs to be able to redirect/accept any valid version of Snort to a ruleset, but in any case, it can cause pulledpork to fail to fetch rule sets.