main/lxc: skip rootfs pinning for read-only rootfs
Without this patch, read-only rootfs containers fails to start.
Backport: https://github.com/lxc/lxc/pull/3844
Edited by Danct12
Without this patch, read-only rootfs containers fails to start.
Backport: https://github.com/lxc/lxc/pull/3844