Default binddn is changed to empty string.

This allows to use anonymous bind, if binddn is not provided. Previous
default setting lead to use of unauthenticated bind, which is usually
disabled in LDAP server configurations.

nginx-ldap-auth-daemon.py

@@ -144,7 +144,7 @@ class LDAPAuthHandler(AuthHandler):
              'url': ('X-Ldap-URL', None),
              'basedn': ('X-Ldap-BaseDN', None),
              'template': ('X-Ldap-Template', '(cn=%(username)s)'),
-             'binddn': ('X-Ldap-BindDN', 'cn=anonymous'),
+             'binddn': ('X-Ldap-BindDN', ''),
              'bindpasswd': ('X-Ldap-BindPass', ''),
              'cookiename': ('X-CookieName', '')
         }