Split colored conflict resolution to helper function, unify callers
- The cases in handleOverlappedFiles() and handleInstInstalledFile() only
differ by presence of "other file state", unify the copy-paste code
to helper function and comment a bit more.
- Push all the color fiddling into the helper, eliminating loads of
unnecessary rpmfiFColorIndex() calls in the common case. Also gives
us a single point of control for the color-conflict behavior.
- This is not supposed to change any behavior at all, just refactoring...