On shell 'exit' commands, running shells from pasta, we might get:
Cannot set tty process group (No such process)
as some TTY devices might be unaccessible. This is harmless, but
after commit "pasta: propagate exit code from child command", we'll
get test failures there, at least with dash.
Ignore those explicitly with a ugly workaround: we can't simply do
something like:
exit || :
because the failure is reported by the shell itself once it exits,
regardless of the command evaluation.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>