[BRLTTY] Issue with brltty 5.2 and the "no" screen driver

[Samuel Thibault]

Hello,

I usually use brltty -b xw -x no to test things with brlapi, but
unfortunately with brltty 5.2 this doesn't seem to be working any more,
I have to use -x lx (and thus run as root) to get the brlapi output
actually displayed, otherwise I only get "no screen".  This can be
reproduced by simply running:

brltty -x no

and then running this in python:

import brlapi
c = brlapi.Connection()
c.enterTtyMode()
c.writeText("foo")

Normally, since there is just one BrlAPI client, its output should just
be displayed.  Making currentVirtualTerminal_BaseScreen() return -1
fixes it.  I tried adding to the noScreen driver a
currentVirtualTerminal method returning -1, but it didn't work.

Samuel