Set c$conn (for logging) in new_connection() event.

c$conn was originally set in connection_established(), which is only
used by TCP connections, and in connection_state_remove(). Using
new_connection() allows us to have c$conn available for any connection
and for any script that wants to extend logging to conn.log.

scripts/base/protocols/conn/main.bro

@@ -200,7 +200,7 @@ function set_conn(c: connection, eoc: bool)
 		}
 	}
 
-event connection_established(c: connection) &priority=5
+event new_connection(c: connection) &priority=5
 	{
 	set_conn(c, F);
 	}