Otherwise, when STDOUT is connected to a pipe, it will not get flushed
completely after each message, which might than hangs the installer UI.
Signed-off-by: Christoph Heiss <c.heiss@proxmox.com>
This is used often, among other things also for some abort code, so
move the essence to the UI.
Allows to drop one global variable for proxinstall, which is a nice
side effect.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
