Fix approxidate("never") to always return 0

Commit af66366 introduced the keyword
"never" to be used with approxidate() but defined it with a fixed date
without taking care of timezone. As a result approxidate() will return
a timestamp in the future with a negative timezone.

With this patch, approxidate("never") always return 0 whatever your
timezone is.

Signed-off-by: Olivier Marin <dkr@freesurf.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

date.c

@@ -682,10 +682,8 @@ static void date_am(struct tm *tm, int *num)
 
 static void date_never(struct tm *tm, int *num)
 {
-	tm->tm_mon = tm->tm_wday = tm->tm_yday
-		= tm->tm_hour = tm->tm_min = tm->tm_sec = 0;
-	tm->tm_year = 70;
-	tm->tm_mday = 1;
+	time_t n = 0;
+	localtime_r(&n, tm);
 }
 
 static const struct special {