Bug#911133: Debian Installer assumes serial console on arm64

[Steve Capper <steve.capper@linaro.org>]

Package: debian-installer
Version: 20180610

Hello,
When trying to install Debian Buster on an arm64 system via a vga
console (for example a BMC console or attached GPU with UEFI +
X86EmulatorPkg) the debian-installer process itself appears to launch
on the serial console (so is invisible to the user).

It is possible to simply alt+F2 to another window, open up a new
console then manually invoke debian-installer from there and proceed
with an install. So this bug is not a blocker.

Cheers,
--
Steve