YUM: Add a check to ignore verification failures on configuration files

* Many RPM packages have files marked as configuration files
* When Bcfg2 reinstalls a package that has a file marked as
  config(noreplace), it doesn't replace the file anyway.
* This change ignores verification failures on file that is marked as
  a configuration file if the fail is marked as checksum, size, mode,
  user, group or mtime.
* It doesn't distinguish the noreplace and replace kinds of files.