general yum-dump.py improvements

yum-dump.py isn't going away in the near future so lets improve it. Immediate issues are

• trapping and handling errors with sane output readable in chef. python backtraces coming out of chef error output are hard to read.
• stop using deprecated api methods
• sorting output to help with debugging rather than just dumping the list verbatim
• define some methods to make the thing more readable - get rid of the giant try/catch
• test the thing as root/non root on centos 5.6/rhel 4/fedora 14 and try to create some config issues