[libgepub/rust] Fixed page next and page prev signals

[Daniel Garcia Moreno <danigm src gnome org>]

commit c4a4f25cccc6ff931672ac676f861a71429db005
Author: Daniel García Moreno <danigm wadobo com>
Date:   Mon Mar 13 17:03:53 2017 +0100

    Fixed page next and page prev signals

 libgepub/gepub-doc.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/libgepub/gepub-doc.c b/libgepub/gepub-doc.c
index 51e8a95..6630805 100644
--- a/libgepub/gepub-doc.c
+++ b/libgepub/gepub-doc.c
@@ -313,8 +313,11 @@ gepub_doc_get_current_with_epub_uris (GepubDoc *doc)
 gboolean
 gepub_doc_go_next (GepubDoc *doc)
 {
-    g_object_notify_by_pspec (G_OBJECT (doc), properties[PROP_PAGE]);
-    return epub_next_page (doc->rust_epub_doc);
+    gboolean isok = epub_next_page (doc->rust_epub_doc);
+    if (isok) {
+        g_object_notify_by_pspec (G_OBJECT (doc), properties[PROP_PAGE]);
+    }
+    return isok;
 }
 
 /**
@@ -326,8 +329,11 @@ gepub_doc_go_next (GepubDoc *doc)
 gboolean
 gepub_doc_go_prev (GepubDoc *doc)
 {
-    g_object_notify_by_pspec (G_OBJECT (doc), properties[PROP_PAGE]);
-    return epub_prev_page (doc->rust_epub_doc);
+    gboolean isok = epub_prev_page (doc->rust_epub_doc);
+    if (isok) {
+        g_object_notify_by_pspec (G_OBJECT (doc), properties[PROP_PAGE]);
+    }
+    return isok;
 }
 
 /**