Fix issue where not all pkgs_to_not_remove are checked.

pkgs_to_not_remove gets modified during the for loop
and so skips some packages.

This fix causes the loop to re-evaluate remaining
packages without skipping any.
Check for counterparts using the original and new package sourcerpm name

The sourcerpm name usually matches the base prefix
for naming purposes, so can be used instead of
needing the original and replacements to match the
base prefix.
Use found package prefixes with the provides auto resolver.

Packages needing to be replaced that are generated
from the same sourcerpm should also use the found
prefixes rather than package names
Merge pull request #4 from andytson/pkgs_to_not_remove_fix

Fix issue where not all pkgs_to_not_remove are checked.
fixing some conflicts from previous pull request to this
removing spec file, see https://github.com/iuscommunity-pkg/yum-plugin-replace