[evince] libdocument: Fix return type for attachment's date

[Germán Poo-Caamaño <gpoo src gnome org>]

commit e50b60d7eaf2ab2e0fa7b73f8af7677659b43d3b
Author: Germán Poo-Caamaño <gpoo gnome org>
Date:   Tue Nov 13 11:07:28 2018 -0300

    libdocument: Fix return type for attachment's date

 libdocument/ev-attachment.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/libdocument/ev-attachment.c b/libdocument/ev-attachment.c
index 1e96a8b0..1ad2ca71 100644
--- a/libdocument/ev-attachment.c
+++ b/libdocument/ev-attachment.c
@@ -275,7 +275,7 @@ ev_attachment_get_modification_date (EvAttachment *attachment)
 {
        EvAttachmentPrivate *priv;
 
-       g_return_val_if_fail (EV_IS_ATTACHMENT (attachment), NULL);
+       g_return_val_if_fail (EV_IS_ATTACHMENT (attachment), 0);
 
        priv = GET_PRIVATE (attachment);
 
@@ -287,7 +287,7 @@ ev_attachment_get_creation_date (EvAttachment *attachment)
 {
        EvAttachmentPrivate *priv;
 
-       g_return_val_if_fail (EV_IS_ATTACHMENT (attachment), NULL);
+       g_return_val_if_fail (EV_IS_ATTACHMENT (attachment), 0);
 
        priv = GET_PRIVATE (attachment);