stage-2: Don't run hwclock in containers

nixos/modules/system/boot/stage-2-init.sh

@@ -164,7 +164,9 @@ $systemConfig/activate
 # Restore the system time from the hardware clock.  We do this after
 # running the activation script to be sure that /etc/localtime points
 # at the current time zone.
-hwclock --hctosys
+if [ -e /dev/rtc ]; then
+    hwclock --hctosys
+fi
 
 
 # Record the boot configuration.