clients: Fix shell background image setting.

If weston.ini is not setting background-image path,
then desktop-shell sets ${DATDIR}/weston/pattern.png
as background. However in this case  width and height
is set to 1 during background config and is being
scaled to avoid allocation of buffer.

This behavior is not right. Along with background-image
path, we should also check if background-color is set.
If background color is set, then only scale 1x1 buffer.

This would allow to set pattern.png as default wallpaper
of weston correctly, if background-color is also not set
in weston.ini file.

Fixes: 3623e46dc5
Signed-off-by: Tanmay Shah <tanmay@codeaurora.org>

clients/desktop-shell.c

@@ -849,7 +849,7 @@ background_configure(void *data,
 		return;
 	}
 
-	if (!background->image) {
+	if (!background->image && background->color) {
 		widget_set_viewport_destination(background->widget, width, height);
 		width = 1;
 		height = 1;