makepkg: properly detect the last rev for all VCS types, remove darcslukeshu-versiondetect

The automatic version detection for VCS systems was
inconsistant/incomplete. In completing it, I removed darcs from the
list. I believe that this is acceptable because:

 * darcs isn't packaged for Arch
 * I couldn't find a PKGBUILD that uses it, in an official repo or the AUR

To sumarize how each of the other VCS systems changed:

 * cvs: use "r{rev}" instead of the current date
 * git: use the date down to the minute of the last commit, rather than the
   current date.
 * svn: use "r{rev}" instead of "{rev}
 * bzr: use "r{rev}" instead of "{rev}
 * hg: use "r{rev}" instead of "{rev}, don't do a pull before

0 files changed, 0 insertions, 0 deletions