Similar to https://github.com/Alexpux/MINGW-packages/pull/2878
this adjusts the pkgbase names of all packages to match the directory
name the PKGBUILD is in.
The motivation for this is to provide links to PKGBUILD sources and
git history from the web interface.
The "dwz" directory is deleted as it just contains an older copy of the
elfutils PKGBUILD (elfutils isn't in the repo)
