check_http: Don't let "-N" expect an argument

Fix the problem that check_http's "-N" option expects an argument
although it shouldn't.  The corresponding long option ("--no-body")
wasn't affected.

This error was introduced in ee3c4014d511e105489b081390636cacd4c53e3f.
Thanks to Kerry Hughes for reporting it on the devel@ list.

plugins/check_http.c

@@ -257,7 +257,7 @@ process_arguments (int argc, char **argv)
   }
 
   while (1) {
-    c = getopt_long (argc, argv, "Vvh46t:c:w:A:k:H:P:j:T:I:a:b:d:e:p:s:R:r:u:f:C:J:K:nlLS::m:M:N:E", longopts, &option);
+    c = getopt_long (argc, argv, "Vvh46t:c:w:A:k:H:P:j:T:I:a:b:d:e:p:s:R:r:u:f:C:J:K:nlLS::m:M:NE", longopts, &option);
     if (c == -1 || c == EOF)
       break;