map: avoid exceptions when wp module not loaded

Author: peterbarker

MAVProxy/modules/mavproxy_map/__init__.py

@@ -1029,7 +1029,11 @@ def mavlink_packet(self, m):
 
     def check_redisplay_waypoints(self):
         # if the waypoints have changed, redisplay
-        last_wp_change = self.module('wp').wploader.last_change
+        wp_module = self.module('wp')
+        if wp_module is None:
+            '''wp nodule not loaded'''
+            return
+        last_wp_change = wp_module.wploader.last_change
         if self.wp_change_time != last_wp_change and abs(time.time() - last_wp_change) > 1:
             self.wp_change_time = last_wp_change
             self.display_waypoints()