Make sure that ActivityBuffer is finished before database commits.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16722 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/CMFActivity/ActivityBuffer.py

@@ -186,3 +186,7 @@ class ActivityBuffer(TM):
     self._register()
     buffer = self._getBuffer()
     buffer.flushed_activity.append((activity, message))
+
+  def sortKey(self, *ignored):
+    """Activities must be finished before databases commit transactions."""
+    return -1