cratHighlighterSubpages.pl: Hardcode program name in UA

Using `$PROGRAM_NAME`, as introduced in 1200e39, just doesn't work in the user agent, or elsewhere.  The attempted fix in 51452a5 also doesn't, what it gets on toolforge is something like `/data/project/` then the botname then the path to the script.  Alas.

crathighlighter/cratHighlighterSubpages.pl

@@ -209,7 +209,7 @@ sub mwLogin {
 			     on_error => \&dieNice,
 			     use_http_get => '1' # use GET where appropriate
 			    });
-  $mw->{ua}->agent("$PROGRAM_NAME (".$mw->{ua}->agent.')');
+  $mw->{ua}->agent('cratHighlighterSubpages.pl ('.$mw->{ua}->agent.')');
   $mw->login({lgname => $username, lgpassword => $password});
 
   return $mw;