issue#86 Problem with "Provide avatar" field with user_sql 4.2.1

lib/Backend/UserBackend.php

@@ -555,7 +555,7 @@ final class UserBackend extends ABackend implements
         );
 
         if (empty($this->properties[DB::USER_AVATAR_COLUMN])) {
-            return false;
+            return !empty($this->properties[Opt::PROVIDE_AVATAR]);
         }
 
         $user = $this->userRepository->findByUid($uid);

lib/Constant/Opt.php

@@ -37,6 +37,7 @@ final class Opt
     const NAME_CHANGE = "opt.name_change";
     const PASSWORD_CHANGE = "opt.password_change";
     const PREPEND_SALT = "opt.prepend_salt";
+    const PROVIDE_AVATAR = "opt.provide_avatar";
     const QUOTA_SYNC = "opt.quota_sync";
     const REVERSE_ACTIVE = "opt.reverse_active";
     const USE_CACHE = "opt.use_cache";