Bump xorg-gtest.m4 serial number
Bump xorg-gtest.m4 serial number

Commit e88bef60ba0208c385bef7fcecdc2e467b94f022 changed the
xorg-gtest.m4 macro script. The serial number needs to be bumped so that
aclocal will copy the newer script into existing packages.

Signed-off-by: Chase Douglas <69e02ec421aa70a149511825d897f2549ceee9a2@canonical.com>

freedesktop-unofficial-mirror/xorg__test__xorg-gtest,freedesktop-unofficial-mirror/xorg__test__xorg-gtest,freedesktop-unofficial-mirror/xorg__test__xorg-gtest