work around ankidroid getbool bug

anki/deck.py

@@ -2916,6 +2916,12 @@ select id from facts where spaceUntil like :_ff_%d escape '\\'""" % c
         ret = self.s.scalar("select value from deckVars where key = :k",
                             k=key)
         if ret is not None:
+            # hack to work around ankidroid bug
+            if ret.lower() == "true":
+                return True
+            elif ret.lower() == "false":
+                return False
+            else:
                 ret = not not int(ret)
         return ret