testback.c: remove emacs magic comment.

It looks as if Ben put that in when he originally wrote the file,
since it refers to a C file style called 'simon', which isn't what I
call my preferred style in _my_ Emacs preferences, but might plausibly
be what he called it in his.

It causes an annoying error every time I load the source file into
Emacs, because it refers to a nonexistent style name. And surely it
will do the same to almost all other Emacs users. Get rid of it.

otherbackends/testback.c

@@ -211,11 +211,3 @@ static int null_cfg_info(Backend *be)
 {
     return 0;
 }
-
-
-/*
- * Emacs magic:
- * Local Variables:
- * c-file-style: "simon"
- * End:
- */