LXC: ArchLinux: Use generic ARMv7 root file system

Currently the Mirabox specific root file system is used to create
an ArchLinux container on Turris OS.

But neither the Mirabox specific firmware nor the Mirabox specific
configuration shipped with this root file system is required for
the LXC use case; worse, the Mirabox specific configuration has to be
partially removed by the generate-lxc.sh script, because it conflicts
with the LXC setup.

Let's just use the generic ARMv7 root file system instead.

lxc-generator/generate-lxc.sh

@@ -76,19 +76,12 @@ get_lxc_url() {
     echo http://images.linuxcontainers.org/images/$1/default/`wget -O - http://images.linuxcontainers.org/images/$1/default | sed -n 's|.*href="\./\(20[^/]*\)/.*|\1|p' | sort | tail -n 1`/rootfs.tar.xz
 }
 
-get_arch() {
-    wget http://os.archlinuxarm.org/os/ArchLinuxARM-mirabox-latest.tar.gz && \
-    gzip -d ArchLinuxARM-mirabox-latest.tar.gz && \
-    sed -i 's|/dev/sda1[[:blank:]]\([[:blank:]]*\)/boot\([[:blank:]]*\)vfat|#/dev/sda1\1/boot\2vfat|' ArchLinuxARM-mirabox-latest.tar
-}
-
 add_image "Turris_OS" "stable" "armv7l" https://repo.turris.cz/omnia/medkit/omnia-medkit-latest.tar.gz
 add_image "Turris_OS" "stable" "ppc" "https://repo.turris.cz/turris/medkit/medkit.tar.xz"
 add_image "Alpine" "3.7" "armv7l" "http://dl-cdn.alpinelinux.org/alpine/v3.7/releases/armhf/alpine-minirootfs-3.7.1-armhf.tar.gz"
 add_image "Alpine" "3.8" "armv7l" "http://dl-cdn.alpinelinux.org/alpine/v3.8/releases/armhf/alpine-minirootfs-3.8.1-armhf.tar.gz"
 add_image "Alpine" "Edge" "armv7l" "`get_lxc_url alpine/edge/armhf`"
-get_arch
-add_image "ArchLinux" "latest" "armv7l" "`pwd`/ArchLinuxARM-mirabox-latest.tar"
+add_image "ArchLinux" "latest" "armv7l" "http://os.archlinuxarm.org/os/ArchLinuxARM-armv7-latest.tar.gz"
 add_image "Debian" "Jessie" "armv7l" "`get_lxc_url debian/jessie/armhf`"
 add_image "Debian" "Stretch" "armv7l" "`get_lxc_url debian/stretch/armhf`"
 add_image "Debian" "Buster" "armv7l" "`get_lxc_url debian/buster/armhf`"