Fix: Ensure that LadderService continues to process matches (#449)

* Ensure that LadderService continues to process matches if it encounters an error

* Add searches to the logging statement

This info is probably redundant because there should be matchmakerqueue 
logging right before it, but who the heck knows. Better to be safe than 
sorry I guess.

server/ladder_service.py

@@ -83,16 +83,22 @@ def inform_player(self, player: Player):
 
     async def handle_queue_matches(self):
         async for s1, s2 in self.queues["ladder1v1"].iter_matches():
-            assert len(s1.players) == 1
-            assert len(s2.players) == 1
-            p1, p2 = s1.players[0], s2.players[0]
-            msg = {
-                "command": "match_found",
-                "queue": "ladder1v1"
-            }
-            p1.lobby_connection.send(msg)
-            p2.lobby_connection.send(msg)
-            asyncio.ensure_future(self.start_game(p1, p2))
+            try:
+                assert len(s1.players) == 1
+                assert len(s2.players) == 1
+                p1, p2 = s1.players[0], s2.players[0]
+                msg = {
+                    "command": "match_found",
+                    "queue": "ladder1v1"
+                }
+                p1.lobby_connection.send(msg)
+                p2.lobby_connection.send(msg)
+                asyncio.ensure_future(self.start_game(p1, p2))
+            except Exception as e:
+                self._logger.exception(
+                    "Error processing match between searches %s, and %s: %s",
+                    s1, s2, e
+                )
 
     async def start_game(self, host: Player, guest: Player):
         self._logger.debug("Starting ladder game between %s and %s", host, guest)