Some packages installed on your system have a broken upgrade path from CentOS 6 to CentOS 7 (that is, the version of the package is lower in CentOS 7).
This situation might cause a failure of the redhat-upgrade-tool run, which in turn might leave the upgraded system in an inconsistent state, with CentOS 6 and CentOS 7 packages mixed together. The Preupgrade Assistant installs a plug-in for the CentOS Upgrade Tool to mitigate this risk, so now the CentOS Upgrade Tool should migrate even the packages with a broken upgrade path. Check that everything is as expected after the upgrade. Optionally, if possible, remove the packages with a broken upgrade path from your CentOS 6 system.
