Restored "maxValidityInterval" to P10D

Author: malavolti

idem-fedops/HOWTO-Shibboleth/Identity Provider/Ubuntu/HOWTO Install and Configure a Shibboleth IdP v3.2.1 on Ubuntu Linux LTS 16.04 with Apache2 + Jetty9.md

@@ -693,7 +693,7 @@
                 Require a validUntil XML attribute on the root element and
                 make sure its value is no more than 10 days into the future.
             -->
-            <MetadataFilter xsi:type="RequiredValidUntil" maxValidityInterval="P6D"/>
+            <MetadataFilter xsi:type="RequiredValidUntil" maxValidityInterval="P10D"/>
 
             <!-- Consume all SP metadata in the aggregate -->
             <MetadataFilter xsi:type="EntityRoleWhiteList">