[yelp] yelp-window: NULL-check page_title before strcmping it

[Shaun McCance <shaunm src gnome org>]

commit 30b8883338e5f6df1898c72df8dea490d61f2a0f
Author: Shaun McCance <shaunm redhat com>
Date:   Wed Aug 19 09:38:19 2015 -0400

    yelp-window: NULL-check page_title before strcmping it

 src/yelp-window.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/yelp-window.c b/src/yelp-window.c
index a45e47d..5dbf6eb 100644
--- a/src/yelp-window.c
+++ b/src/yelp-window.c
@@ -1187,7 +1187,7 @@ view_root_title (YelpView    *view,
     else
         gtk_header_bar_set_title (GTK_HEADER_BAR (priv->header), _("Help"));
 
-    if (root_title && strcmp (root_title, page_title))
+    if (root_title && (page_title == NULL || strcmp (root_title, page_title)))
         gtk_header_bar_set_subtitle (GTK_HEADER_BAR (priv->header), root_title);
     else
         gtk_header_bar_set_subtitle (GTK_HEADER_BAR (priv->header), NULL);