stretch: install net-tools

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>

lib/stretch-preseed.cfg

@@ -58,7 +58,7 @@ d-i partman-auto/disk string /dev/mmcblk0
 d-i partman-auto/expert_recipe_file string /partition_recipe
 
 # Individual additional packages to install
-d-i pkgsel/include string bash dosfstools initramfs-tools rcn-ee-archive-keyring util-linux wget board-firmware
+d-i pkgsel/include string bash dosfstools initramfs-tools rcn-ee-archive-keyring util-linux wget board-firmware net-tools
 
 # Whether to upgrade packages after debootstrap.
 # Allowed values: none, safe-upgrade, full-upgrade