[gnome-software] trivial: Fix a build warning

[Richard Hughes <rhughes src gnome org>]

commit cb968b173af8c45d0a40058694bda67775e84cae
Author: Richard Hughes <richard hughsie com>
Date:   Wed Aug 6 15:20:45 2014 +0200

    trivial: Fix a build warning

 src/gs-screenshot-image.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/gs-screenshot-image.c b/src/gs-screenshot-image.c
index dc5acab..55b94f3 100644
--- a/src/gs-screenshot-image.c
+++ b/src/gs-screenshot-image.c
@@ -241,8 +241,8 @@ gs_screenshot_image_complete_cb (SoupSession *session,
 
        /* is image size destination size unknown or exactly the correct size */
        if (priv->width == G_MAXUINT || priv->height == G_MAXUINT ||
-           (priv->width == gdk_pixbuf_get_width (pixbuf) &&
-            priv->height == gdk_pixbuf_get_height (pixbuf))) {
+           (priv->width == (guint) gdk_pixbuf_get_width (pixbuf) &&
+            priv->height == (guint) gdk_pixbuf_get_height (pixbuf))) {
                ret = g_file_set_contents (priv->filename,
                                           msg->response_body->data,
                                           msg->response_body->length,