test1513: make sure the callback is only called once

tests/data/test1513

@@ -42,5 +42,8 @@ http://%HOSTIP:%HTTPPORT/1513
 <errorcode>
 42
 </errorcode>
+<stdout>
+PROGRESSFUNCTION called
+</stdout>
 </verify>
 </testcase>

tests/libtest/lib1513.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -41,6 +41,7 @@ static int progressKiller(void *arg,
   (void)dlnow;
   (void)ultotal;
   (void)ulnow;
+  printf("PROGRESSFUNCTION called\n");
   return 1;
 }