backported metakit fix from HEAD

Author: Richard Jones

CHANGES.txt

@@ -8,6 +8,7 @@ are given with the most recent entry first.
 - open server logfile unbuffered
 - revert StringHTMLProperty to not hyperlink text by default
 - fixes to CGI form handling
+- fix unlink bug in metakit backend
 
 
 2003-01-10 0.5.4

roundup/backends/back_metakit.py

@@ -422,7 +422,7 @@ def set(self, nodeid, **propvalues):
                 if self.do_journal and prop.do_journal:
                     # register the unlink with the old linked node
                     if oldvalue:
-                        self.db.addjournal(link_class, value, _UNLINK,
+                        self.db.addjournal(link_class, oldvalue, _UNLINK,
                             (self.classname, str(row.id), key))
 
                     # register the link with the newly linked node