(fix) avoid going to far when checking logins if no login is defined

SoObjects/SOGo/LDAPSource.m

@@ -1090,7 +1090,7 @@ groupObjectClasses: (NSArray *) newGroupObjectClasses
         // We check if our entry is a group. If so, we set the
         // 'isGroup' custom attribute.
         gclasses = [groupObjectClasses objectEnumerator];
-        while (gclass = [gclasses nextObject])
+        while ((gclass = [gclasses nextObject]))
          if ([classes containsObject: [gclass lowercaseString]])
            {
              [ldifRecord setObject: [NSNumber numberWithInt: 1]

SoObjects/SOGo/SOGoUserManager.m

@@ -537,6 +537,9 @@ static Class NSNullK;
   SOGoSystemDefaults *sd;
   BOOL checkOK;
 
+  if (!_login)
+    return NO;
+
   sd = [SOGoSystemDefaults sharedSystemDefaults];
 
   username = _login;