libxtst: 1.2.2 -> 1.2.3

libxtst: 1.2.2 -> 1.2.3

Upgrade libxtst from 1.2.2 to 1.2.3 to address:
Out of Bounds Write Denial of Service Vulnerability, CVE-2016-7951

References:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7951
https://cgit.freedesktop.org/xorg/lib/libXtst/commit/?id=9556ad67af3129ec4a7a4f4b54a0d59701beeae3

(From OE-Core rev: 02a0dd90c3f3b1fc6ebddc17feb824d11848b2a7)

Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>