Exclude the old SimpleSAML/Auth/LDAP class from code coverage

Signed-off-by: Jaime Pérez Crespo <jaime.perez@uninett.no>

phpunit.xml

@@ -22,6 +22,7 @@
                 <directory>./vendor/</directory>
                 <directory>./tests/</directory>
                 <file>./lib/SimpleSAML/Utils/HttpAdapter.php</file>
+                <file>./lib/SimpleSAML/Auth/LDAP.php</file>
             </exclude>
         </whitelist>
     </filter>