LDAP: extend LDAP wrapper search method for sizelimit, improves performance in wizard
throw an info message, when base dn test failed
Wizard: disable LDAP referrals, fixes #6670
Wizard: enable base DN for editing, if not base DN could have been detected. Also part of fix for #6670
Rephrase and clarify log message
Merge pull request #7081 from owncloud/fix_6670

LDAP: Wizard cannot determine Base DN in some cases, fixes #6670