bsdinstall: Copy /etc/localtime as symlink in jail script

Without -P (or -R, which defaults to enabling -P) symlinks are
dereferenced and so the target file is copied, not the symlink itself.

Fixes:	5e16809 ("tzsetup: symlink /etc/localtime instead of copying")

Author: jrtc27

usr.sbin/bsdinstall/scripts/jail

@@ -207,7 +207,7 @@ fi
 trap error SIGINT	# SIGINT is bad again
 bsdinstall config  || error "Failed to save config"
 cp /etc/resolv.conf $1/etc
-cp /etc/localtime $1/etc
+cp -P /etc/localtime $1/etc
 cp /var/db/zoneinfo $1/var/db
 
 # Run post-install script