Tweak %extend templates

Previous commit turned on the generation of an extra extend function
wrapper of a member template function when %template was inside a %extend
block instead of calling the real member template - reversed this side
effect.

Source/CParse/parser.y

@@ -372,7 +372,8 @@ static void add_symbols(Node *n) {
     }
 
     if (extendmode) {
-      Setattr(n,"isextendmember","1");
+      if (!Getattr(n, "template"))
+        SetFlag(n,"isextendmember");
     }
 
     if (!isfriend && inclass) {