fix rescheduling of relearn cards (#874)

- need to reset 'odue'
- also need to reset 'due' so the new cards don't take on - timestamp
  positions

anki/sched.py

@@ -1264,7 +1264,7 @@ To study outside of the normal schedule, click the Custom Study button below."""
     def forgetCards(self, ids):
         "Put cards at the end of the new queue."
         self.col.db.execute(
-            "update cards set type=0,queue=0,ivl=0,factor=? where id in "+
+            "update cards set type=0,queue=0,ivl=0,odue=0,due=0,factor=? where id in "+
             ids2str(ids), 2500)
         pmax = self.col.db.scalar(
             "select max(due) from cards where type=0") or 0