Fix obvious typo in threaded test.
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 2777b22..9281abc 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -846,7 +846,7 @@
         th2.start()
 
         self.finish1.wait()
-        self.finish1.wait()
+        self.finish2.wait()
         return
 
     if threading is None: