[gnome-sudoku] Remove now unused stats-very-hard.png figure

[Andre Klapper <aklapper src gnome org>]

commit fa46013e3296f5e4f6f59a629b05fdfb0f3addaa
Author: Andre Klapper <a9016009 gmx de>
Date:   Sun Sep 24 14:43:01 2017 +0200

    Remove now unused stats-very-hard.png figure

 help/C/figures/stats-very-hard.png |  Bin 28325 -> 0 bytes
 help/Makefile.am                   |    1 -
 2 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/help/Makefile.am b/help/Makefile.am
index ec4bf40..b24ab06 100644
--- a/help/Makefile.am
+++ b/help/Makefile.am
@@ -7,7 +7,6 @@ HELP_MEDIA = \
        figures/possible-numbers.png    \
        figures/resuming.png            \
        figures/rowcolumnbox.png        \
-       figures/stats-very-hard.png     \
        figures/strategy1.png           \
        figures/strategy2.png           \
        figures/trackers.webm