We now get unit test failures hitting this timeout. That is
likely a new bug introduced somewhere, but to rule out that
the timeout is simply too short, increase it.
Note that "test-client.py" currently only tests nmcli. But what it does
is to spawn test-networkmanager-service.py and run nmcli against it.
As such, it could really be used to test any NetworkManager client
against the stub service. Hence this test is not under
"src/nmcli/tests", but under "src/tests/client/" where it is more
general.