net: run.sh: fix infinite "q Enter to close" msgs

Fix the logic that is supposed to display a "q Enter to close" message
once and wait for user input, in case one of the Osmocom programs
crashed.

Explicitly read from /dev/tty, as it may not be connected as default
stdin anymore at this point. This happens when using the new code paths
with tmux as terminal, but also happened before recent refactorings for
me with all terminals.

Related: https://media.ccc.de/v/osmodevcall-20211210-osmith-osmo-dev-ttcn3#t=801
Change-Id: Iebb799493f76fd57f24b15c998ded2bd8e284e6b
1 file changed