Improvements for the upgrade proc:  * Don't mess with which version is active at the start (https://trac.macports.org/ticket/16085)  * Don't uninstall old versions due to epoch override or -f unless truly necessary  * The variants from the active version are now used for the new version, unless there is no active version in which case it uses the most recent version (as previously)  * Epoch is now considered when finding the most recent installed version
Improvements for the upgrade proc:
 * Don't mess with which version is active at the start (https://trac.macports.org/ticket/16085)
 * Don't uninstall old versions due to epoch override or -f unless truly necessary
 * The variants from the active version are now used for the new version, unless there is no active version in which case it uses the most recent version (as previously)
 * Epoch is now considered when finding the most recent installed version

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@47771 d073be05-634f-4543-b044-5fe20cf6d1d6

neverpanic/macports-base,danchr/macports-base,macports/macports-base,neverpanic/macports-base,danchr/macports-base,macports/macports-base