[five-or-more] Fix theme loading

[Michael Catanzaro <mcatanzaro src gnome org>]

commit c5e3baacf87e64db33a6cbb59f197fc39a2a0044
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Aug 17 12:36:28 2016 +0200

    Fix theme loading
    
    No idea when this broke. It was working for me just two weeks ago....

 src/five-or-more.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/five-or-more.c b/src/five-or-more.c
index f2f52be..16d8cba 100644
--- a/src/five-or-more.c
+++ b/src/five-or-more.c
@@ -224,6 +224,9 @@ refresh_pixmaps (void)
   if (!ball_surface)
     return;
 
+  if (!boxsize)
+    return;
+
   if (ball_preimage) {
     ball_pixbuf = games_preimage_render (ball_preimage, 4 * boxsize,
                                          7 * boxsize);