bottle drop: Be less aggressive about scheduling

src/modules/bottle_drop/bottle_drop.cpp

@@ -222,7 +222,7 @@ BottleDrop::start()
 	/* start the task */
 	_main_task = task_spawn_cmd("bottle_drop",
 				    SCHED_DEFAULT,
-				    SCHED_PRIORITY_MAX - 5,
+				    SCHED_PRIORITY_DEFAULT + 15,
 				    2048,
 				    (main_t)&BottleDrop::task_main_trampoline,
 				    nullptr);