Vagrant package with relative path

Seems like the vagrant package expects the path to be relative to it's root= initialisation. Without a relative path it lead to some weird errors were it tried to copy the absolute path relative to it's root

makebuildserver

@@ -379,7 +379,8 @@ def main():
     if os.path.exists(boxfile):
         os.remove(boxfile)
 
-    v.package(output=boxfile)
+    boxfile_rel = os.path.relpath(boxfile, start=serverdir)
+    v.package(output=boxfile_rel)
 
     logging.info("Adding box")
     vm.box_add('buildserver', boxfile, force=True)