Leave the host's falling bipeds to the host on a client

A client ran biped_falling_damage's outside-the-world erase on the host's
AI bipeds too: object_delete refuses them there (network_objects_may_delete),
so nothing was erased, but each was logged as erased. On a co-op client of a
crowded game that was hundreds of false warnings. The host erases them, and
its delete reaches the clients.

source/units/bipeds.c

@@ -277,6 +277,10 @@ symbols in this file:
 #include "structures/structure_bsp_definitions.h"
 #include "network_coop.h" /* port: port/linux/game/network_coop.c */
 
+/* port: port/linux/game/network_objects.c's (a client deletes the host's
+objects on the host's word alone) */
+boolean network_objects_may_delete(long object_index);
+
 /* port: an unarmed player's melee's length, in ticks (a weapon's is about
 this: its first person melee animation, sped up a quarter) */
 #define UNARMED_MELEE_TICKS 16
@@ -830,9 +834,12 @@ static void biped_falling_damage(
 				object_cause_damage(&damage, biped_index, NONE, NONE, NONE, NULL);
 			}
 
+			/* (port: not the host's biped on a client, which the host erases:
+			the delete was refused, and logged as done) */
 			if (!game_engine_running() &&
 				TEST_FLAG(biped->object.flags, _object_outside_of_map_bit) &&
-				player_index_from_unit_index(biped_index) == NONE)
+				player_index_from_unit_index(biped_index) == NONE &&
+				network_objects_may_delete(biped_index))
 			{
 				long actor_index = biped->unit.swarm_actor_index;