Reorder things slightly

The "slotevent" test would eject the card, not wait for the result, and
then exit. This would cause the "mechlist" test to fail due to a
CKR_DEVICE_ERROR.

We should possibly figure out if we can actually fix the
CKR_DEVICE_ERROR (although that may be something we can't actually do),
but for now at least keep things in a proper state when we SKIP a test.
Provide a more detailed error message when things fail
Don't forget to return TRUE when the device is already open
We don't need a delay *that* long
Whitespace cleanup
Fix check

"dev" is a char* containing a device name; "robot_dev" is an fd.

Verify the correct file descriptor...
Decouple "want dialogs" flag from "have robot" flag.
Produce an error message when the user tried something that doesn't work.