tests: make long message-id a realistic one.
Otherwise, python3.8 bombs out with UnboundLocalError https://github.com/python/cpython/pull/13397/files#r341968031
Signed-off-by: Dimitri John Ledkov xnox@ubuntu.com
Otherwise, python3.8 bombs out with UnboundLocalError https://github.com/python/cpython/pull/13397/files#r341968031
Signed-off-by: Dimitri John Ledkov xnox@ubuntu.com