factory_test_tools: fix results for HWQual tests

factory_test_tools: fix results for HWQual tests

- HWQual needs to allow legacy search when there's still possible case of  ''
  (not present), which were not allowed by gft_hwcomp. This CL removes 'not
  present' before checking legacy search

- HWQual needs to also get better error output messages, especially when above
  change is applied.

BUG=chrome-os-partner:3195
TEST=/gft_hwcomp.py approved_components
    # on system with / without approved 3G, seeing success
    # on incompatible system, seeing  message like:
    {'part_id_cardreader': ['Actual: Not Present', 'Expected: XXXX:0138'],
     'part_id_ethernet': ['Actual: 0b95:7720 ASIX Elec. Corp. AX88x72A',
                           'Expected: XXXX:1063 | Not Present']}

Change-Id: Ie20111d33a4ca8e1d7743ea5bbb98cb6a8b047d4

R=waihong@chromium.org

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=d667460

[Tom Wai-Hong Tam, 2011-04-19 03:35:38]

LGTM