Remove the apache tag synonym, and ban it (is this possible?).
Remove the synonym and create the tag, with a descriptor of what apache is, referencing the other two tags.
Ok, the apache tag is now blacklisted:
Along with this comes the requirement that a version-specific tag exists for each Apache version being asked about. In practice, this isn't likely to be too different from what was already occurring (since the raw apache tag was being silently renamed to apache-2.2), but be aware that some amount of confusion or mistagging may result - so be prepared to retag (and create new tags) as needed.
I think that it would be handy to have a generic
apache-2.x tag for answers which are not specific to a particular subversion of apache. I just had one of those a few minutes ago.