Port log level filtering from OC_Log_Owncloud to OC_Log_Syslog.

lib/log/syslog.php

@@ -31,7 +31,10 @@ class OC_Log_Syslog {
 	 * @param int level
 	 */
 	public static function write($app, $message, $level) {
+		$minLevel = min(OC_Config::getValue("loglevel", OC_Log::WARN), OC_Log::ERROR);
+		if ($level >= $minLevel) {
 			$syslog_level = self::$levels[$level];
 			syslog($syslog_level, '{'.$app.'} '.$message);
 		}
 	}
+}