Ticket 49333 - Do not remove versioned man pages
Bug Description: Until resolving ticket 49689 in 50b5449, running
`make clean' removed also man pages which were tracked in the
versioning system (notably man1 and man8).
Fix Description: Bring back only removal of man3 man pages as they are
autogenerated and thus should not be tracked.
https://pagure.io/389-ds-base/issue/49333
Author: mhonek
Review by: mreynolds (thanks!)