package/x11r7/xlib_libXfont: security version bump to 1.5.1

Fixes CVE-2015-1802, CVE-2015-1803, CVE-2015-1804
http://lists.x.org/archives/xorg-announce/2015-March/002551.html
http://lists.x.org/archives/xorg-announce/2015-March/002550.html



Also add hash file.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>