Reconnect after closing socket due to inactivity.

app/src/main/java/org/briarproject/snooze/NetworkClient.java

@@ -59,7 +59,9 @@ class NetworkClient extends Thread {
 		long inactive = System.currentTimeMillis() - lastActive;
 		if (inactive > 2 * keepaliveIntervalMs) {
 			log.log("Inactive for " + (inactive / 1000) + " seconds, closing socket");
-			closeConnection();
+			synchronized (this) {
+				if (socket != null) tryToClose(socket);
+			}
 		}
 	}