bugfix: When generating a NameID from a multivalued attribute, a warning was...

bugfix: When generating a NameID from a multivalued attribute, a warning was logged but the NameID was still generated.

modules/saml/lib/Auth/Process/AttributeNameID.php

@@ -63,6 +63,7 @@ class sspmod_saml_Auth_Process_AttributeNameID extends sspmod_saml_BaseNameIDGen
                 'More than one value in attribute '.var_export($this->attribute, true).
                 ' on user - not generating attribute NameID.'
             );
+            return null;
         }
         $value = array_values($state['Attributes'][$this->attribute]); // just in case the first index is no longer 0
         $value = $value[0];