rtc in localtime: use settimeofday(NULL, tz) instead of hwclock(8)

rtc in localtime: use settimeofday(NULL, tz) instead of hwclock(8)

We check for LOCAL in /etc/adjtime and if needed, ask the kernel to
apply the timezone delta to the system clock.

The very first call of settimeofday() without a time, but a timezone
warps the system clock, so that it properly runs in UTC.