Fix timestamp for test-tick

The earlier test timestamp was too old; I forgot that the bare
unixtime integer had to be after Jan 1, 2000.  This changes
test_tick to use the git-epoch timestamp.

Signed-off-by: Junio C Hamano <junkio@cox.net>

t/test-lib.sh

@@ -99,12 +99,12 @@ trap 'echo >&5 "FATAL: Unexpected exit with code $?"; exit 1' exit
 test_tick () {
 	if test -z "${test_tick+set}"
 	then
-		test_tick=432630000
+		test_tick=1112911993
 	else
 		test_tick=$(($test_tick + 60))
 	fi
-	GIT_COMMITTER_DATE=$test_tick
-	GIT_AUTHOR_DATE=$test_tick
+	GIT_COMMITTER_DATE="$test_tick -0700"
+	GIT_AUTHOR_DATE="$test_tick -0700"
 	export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
 }