Revert "(legacy) please set interface flag one by one...."

This reverts commit 85dd1473.

src/etc/inc/interfaces.lib.inc

@@ -50,12 +50,10 @@ function legacy_interface_listget($flag = '')
     return ($ifs);
 }
 
-function legacy_interface_flags($ifs, $flags, $report_errors=true)
+function legacy_interface_flags($ifs, $flag, $report_errors=true)
 {
     /* $flags isn't escaped because it can be an argument list */
-    foreach (explode(' ', $flags) as $flag) {
-        $cmd = '/sbin/ifconfig ' . escapeshellarg($ifs) . ' ' . $flag;
-    }
+    $cmd = '/sbin/ifconfig ' . escapeshellarg($ifs) . ' ' . $flag;
 
     exec($cmd . ' 2>&1', $out, $ret);
     if (!empty($ret) && $report_errors) {