tests: qpci_unplug_acpi_device_test() should not rely on global_qtest

tests: qpci_unplug_acpi_device_test() should not rely on global_qtest

libqos functions should not use functions that require global_qtest to
be set, since such library functions could also be used by tests that
deal with multiple test states. Add a parameter to this function to
explicitly specify the test state.

Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190508143209.24350-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>