attach_device: Change SKIP into PASS/FAIL

If a failure is expected for an unsupported option, then we should return
PASS not SKIP. Likewise, if it wasn't expected we should return FAIL.
Since expectedly failing is a return of True, analyze_negative_results()
also needs to adjust its expectations with respect to return status.
Merge pull request #52 from jferlan/attach_device

attach_device: Change SKIP into PASS/FAIL