Use OC_Helper::serverHost() in openid settings

apps/user_openid/templates/settings.php

@@ -1,7 +1,7 @@
 <form id="openidform">
 	<fieldset class="personalblock">
 		<strong>OpenID</strong>
-		<?php echo ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 'https' : 'http').'://'.$_SERVER['HTTP_HOST'].OC::$WEBROOT.'/?'; echo OC_User::getUser(); ?><br /><em><?php echo $l->t('you can authenticate to other sites with this address');?></em><br />
+		<?php echo ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 'https' : 'http').'://'.OC_Helper::serverHost().OC::$WEBROOT.'/?'; echo OC_User::getUser(); ?><br /><em><?php echo $l->t('you can authenticate to other sites with this address');?></em><br />
 		<label for="identity"><?php echo $l->t('Authorized OpenID provider');?></label>
 		<input type="text" name="identity" id="identity" value="<?php echo $_['identity']; ?>" placeholder="<?php echo $l->t('Your address at Wordpress, Identi.ca, &hellip;');?>" /><span class="msg"></span>
 	</fieldset>