Merge yum API methods from jfrog fork

[mcandre]

Hi, thank you for publishing a tremendously helpful library for analyzing RPM packages! Some forks such as jfrog have extended the library to analyze Yum metadata as well. Could we merge these changes into the main go-rpm library?

https://github.com/jfrog/go-rpm

[cavaliercoder]

Thanks! I'd be happy to but I don't see the yum API code anywhere? I only see a change to a single bounds check.

master...jfrog:master

[pixdrift]

I believe @mcandre is referring to the yum capabilities here:
https://github.com/jfrog/go-rpm/tree/master/yum

Primarily to interrogate the repomd.xml and primary.xml files generated by createrepo, although it appears the jfrog implementation has chosen to use the sqlite primarydb over the primary.xml file.