The qos dependency files can be found under tests/qtest/libqos and
not under tests/qtest/qos.

Fixes: 1cf4323e ("Move the libqos files under tests/qtest/")
Message-Id: <20200127140245.20065-1-thuth@redhat.com>
Reviewed-by: NLaurent Vivier <lvivier@redhat.com>
Signed-off-by: NThomas Huth <thuth@redhat.com>