Remove declarations that do no have definitions

There is a couple of leftover header files/declarations, which were
fronting implementations that are long gone.

Let's get rid of them.

include/sway/config.h

@@ -449,8 +449,6 @@ void free_sway_variable(struct sway_variable *var);
  */
 char *do_var_replacement(char *str);
 
-struct cmd_results *check_security_config();
-
 int input_identifier_cmp(const void *item, const void *data);
 
 struct input_config *new_input_config(const char* identifier);

include/swaybar/tray/dbus.h

@@ -1,18 +0,0 @@
-#ifndef _SWAYBAR_DBUS_H
-#define _SWAYBAR_DBUS_H
-
-#include <stdbool.h>
-#include <dbus/dbus.h>
-extern DBusConnection *conn;
-
-/**
- * Should be called in main loop to dispatch events
- */
-void dispatch_dbus();
-
-/**
- * Initializes async dbus communication
- */
-int dbus_init();
-
-#endif /* _SWAYBAR_DBUS_H */

include/swaybar/tray/sni_watcher.h

@@ -1,10 +0,0 @@
-#ifndef _SWAYBAR_SNI_WATCHER_H
-#define _SWAYBAR_SNI_WATCHER_H
-
-/**
- * Starts the sni_watcher, the watcher is practically a black box and should
- * only be accessed though functions described in its spec
- */
-int init_sni_watcher();
-
-#endif /* _SWAYBAR_SNI_WATCHER_H */

include/swaybar/tray/tray.h

@@ -1,32 +0,0 @@
-#ifndef _SWAYBAR_TRAY_H
-#define _SWAYBAR_TRAY_H
-
-#include <stdint.h>
-#include <stdbool.h>
-#include "swaybar/tray/dbus.h"
-#include "swaybar/tray/sni.h"
-#include "swaybar/bar.h"
-#include "list.h"
-
-extern struct tray *tray;
-
-struct tray {
-	list_t *items;
-};
-
-/**
- * Processes a mouse event on the bar
- */
-void tray_mouse_event(struct output *output, int x, int y,
-		uint32_t button, uint32_t state);
-
-uint32_t tray_render(struct output *output, struct config *config);
-
-void tray_upkeep(struct bar *bar);
-
-/**
- * Initializes the tray with D-Bus
- */
-void init_tray(struct bar *bar);
-
-#endif /* _SWAYBAR_TRAY_H */