test_digestauth_concurrent: fixed error message

src/testcurl/test_digestauth_concurrent.c

@@ -662,7 +662,7 @@ main (int argc, char *const *argv)
 #if (LIBCURL_VERSION_MAJOR == 7) && (LIBCURL_VERSION_MINOR == 62)
   if (1)
   {
-    fprintf (stderr, "libcurl version 7.62.x has bug in processing"
+    fprintf (stderr, "libcurl version 7.62.x has bug in processing "
              "URI with GET arguments for Digest Auth.\n");
     fprintf (stderr, "This test cannot be performed.\n");
     exit (77);