[gnome-mines] help: Remove unused (and unhelpful) screenshot

[Andre Klapper <aklapper src gnome org>]

commit 5fb7d057f289a8c57278e387acfab60fb871270a
Author: Andre Klapper <a9016009 gmx de>
Date:   Sat Sep 16 22:56:03 2017 +0200

    help: Remove unused (and unhelpful) screenshot

 help/C/figures/imnotsureflagscheckbox.png |  Bin 3493 -> 0 bytes
 help/Makefile.am                          |    1 -
 2 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/help/Makefile.am b/help/Makefile.am
index e9a0f17..67dd8ab 100644
--- a/help/Makefile.am
+++ b/help/Makefile.am
@@ -13,7 +13,6 @@ HELP_MEDIA = \
        figures/hard-hints-2.png \
        figures/hard-hints-3.png \
        figures/highscores.png \
-       figures/imnotsureflagscheckbox.png \
        figures/logo32.png \
        figures/logo.png \
        figures/main-window.png \