_diff_tree_.c: Fix double decref of objects module.

NEWS

@@ -2,6 +2,8 @@
 
  BUG FIXES
 
+  * Fix double decref in _diff_tree.c. (Ted Horst, #715528)
+
   * Fix the build on Windows. (Pascal Quantin)
 
   * Fix get_transport_and_path compatibility with pre-2.6.5 versions of Python.

dulwich/_diff_tree.c

@@ -438,7 +438,6 @@ init_diff_tree(void)
 		goto error;
 	}
 
-	Py_DECREF(objects_mod);
 	Py_DECREF(diff_tree_mod);
 	return;