Better build of the default root image

The image contains locales with the current system locales available
and cleans up the apt cache.

build.sh

@@ -47,14 +47,17 @@ else
     sudo debootstrap \
         --arch=armhf \
         --foreign \
-        --include=sudo,cgpt,vboot-utils,vboot-kernel-utils \
+        --include=sudo,cgpt,vboot-utils,vboot-kernel-utils,locales \
         stretch \
         $MOUNTDIR \
         http://http.debian.net/debian
-        
+
     sudo cp /usr/bin/qemu-arm-static ${MOUNTDIR}/usr/bin/
     sudo chroot ${MOUNTDIR} /debootstrap/debootstrap --second-stage
 
+    sudo cp /etc/locale.gen ${MOUNTDIR}/etc/locale.gen
+    sudo chroot ${MOUNTDIR} locale-gen
+
     sudo tee -a ${MOUNTDIR}/etc/apt/sources.list >/dev/null <<EOF
 deb http://deb.debian.org/debian sid main
 EOF
@@ -71,6 +74,7 @@ EOF
 
     sudo chroot ${MOUNTDIR} apt-get update
     sudo chroot ${MOUNTDIR} apt-get --assume-yes install linux-image-4.8.0-1-armmp-unsigned
+    sudo chroot ${MOUNTDIR} apt-get clean
 
     cd ${MOUNTDIR}
     sudo tar cvf ${CURRENTDIR}/root.tar.gz .