Don't set a default value for reSync argument.

- reSync() is only called in ykval-queue,
	and that sets an $older_than argument.

- additionally, the defaults did not match.

- the value in ykval-queue (via ykval-config) is 10 seconds,
	and the value in reSync($older_than=) was 60 seconds.

- no functional change, just makes things less confusing.

ykval-synclib.php

@@ -251,7 +251,7 @@ class SyncLib
 	}
 
 	// queue daemon
-	public function reSync($older_than=60, $timeout)
+	public function reSync($older_than, $timeout)
 	{
 		$this->log(LOG_DEBUG, 'starting resync');