azure-common: remove bootloader timeout since we can access serial console now

    # Generate a GRUB menu.

    boot.loader.grub.device = "/dev/sda";

    boot.loader.timeout = 0;

    boot.growPartition = true;

    # Don't put old configurations in the GRUB menu.  The user has no

    # way to select them anyway.

    boot.loader.grub.configurationLimit = 0;

    fileSystems."/" = {

      device = "/dev/disk/by-label/nixos";

      fsType = "ext4";