Fix the archlinux package, use correct DROPIN dirs

Without this change the package builds successfully but there is a
file conflict error when installing it.

(cherry picked from commit 4f26267796fa856d1e3a2883494b7cc09221b2e9)

archlinux/PKGBUILD

@@ -69,7 +69,7 @@ package() {
 
   (cd qrexec; make install DESTDIR=$pkgdir SBINDIR=/usr/bin LIBDIR=/usr/lib SYSLIBDIR=/usr/lib)
 
-  make install-vm DESTDIR=$pkgdir SBINDIR=/usr/bin LIBDIR=/usr/lib SYSLIBDIR=/usr/lib DROPIN_DIR=usr/lib/systemd DIST=archlinux
+  make install-vm DESTDIR=$pkgdir SBINDIR=/usr/bin LIBDIR=/usr/lib SYSLIBDIR=/usr/lib SYSTEM_DROPIN_DIR=/usr/lib/systemd/system USER_DROPIN_DIR=/usr/lib/systemd/user DIST=archlinux
 
   # Remove things non wanted in archlinux
   rm -r $pkgdir/etc/yum*