lib-storage: remove attribute accessibility checks

index_storage_attribute_{set,get} should assume that the caller performed
due diligence and checked whether or not the user is allowed to store under
the key.

src/lib-storage/index/index-attribute.c

@@ -192,21 +192,14 @@ index_storage_attribute_get_dict_trans(struct mailbox_transaction_context *t,
 int index_storage_attribute_set(struct mailbox_transaction_context *t,
 				enum mail_attribute_type type, const char *key,
 				const struct mail_attribute_value *value,
-				bool internal_attribute)
+				bool unused ATTR_UNUSED)
 {
 	struct dict_transaction_context *dtrans;
 	const char *mailbox_prefix;
 	bool pvt = type == MAIL_ATTRIBUTE_TYPE_PRIVATE;
 	time_t ts = value->last_change != 0 ? value->last_change : ioloop_time;
 	int ret = 0;
 
-	if (!internal_attribute &&
-	    !MAILBOX_ATTRIBUTE_KEY_IS_USER_ACCESSIBLE(key)) {
-		mail_storage_set_error(t->box->storage, MAIL_ERROR_PARAMS,
-			"Internal attributes cannot be changed directly");
-		return -1;
-	}
-
 	if (index_storage_attribute_get_dict_trans(t, type, &dtrans,
 						   &mailbox_prefix) < 0)
 		return -1;
@@ -234,18 +227,14 @@ int index_storage_attribute_set(struct mailbox_transaction_context *t,
 int index_storage_attribute_get(struct mailbox *box,
 				enum mail_attribute_type type, const char *key,
 				struct mail_attribute_value *value_r,
-				bool internal_attribute)
+				bool unused ATTR_UNUSED)
 {
 	struct dict *dict;
 	const char *mailbox_prefix, *error;
 	int ret;
 
 	memset(value_r, 0, sizeof(*value_r));
 
-	if (!internal_attribute &&
-	    !MAILBOX_ATTRIBUTE_KEY_IS_USER_ACCESSIBLE(key))
-		return 0;
-
 	if (index_storage_get_dict(box, type, &dict, &mailbox_prefix) < 0)
 		return -1;
 

src/lib-storage/index/index-storage.h

@@ -114,11 +114,11 @@ int index_mailbox_get_physical_size(struct mailbox *box,
 int index_storage_attribute_set(struct mailbox_transaction_context *t,
 				enum mail_attribute_type type, const char *key,
 				const struct mail_attribute_value *value,
-				bool internal_attribute);
+				bool unused);
 int index_storage_attribute_get(struct mailbox *box,
 				enum mail_attribute_type type, const char *key,
 				struct mail_attribute_value *value_r,
-				bool internal_attribute);
+				bool unused);
 struct mailbox_attribute_iter *
 index_storage_attribute_iter_init(struct mailbox *box,
 				  enum mail_attribute_type type,