Remove dead function lower_bot_linked

src/botnet.cc

@@ -1813,8 +1813,4 @@ void zapfbot(int idx)
   lostdcc(idx);
 }
 
-void lower_bot_linked(int idx)
-{
-}
-
 /* vim: set sts=2 sw=2 ts=8 et: */

src/botnet.h

@@ -11,7 +11,7 @@ extern tand_t		*tandbot;
 extern party_t		*party;
 extern int		tands;
 
-void lower_bot_linked(int idx);
+#define lower_bot_linked(idx) do {} while (0)
 void answer_local_whom(int, int);
 char *lastbot(const char *) __attribute__((pure));
 int nextbot(const char *) __attribute__((pure));