test_factory.py: Ignore missing properties log file

When creating a test, if a property exists for the platform, but
doesn't exist in the log, it's okay.

TEST=created test w/ log that had property missing.

Change-Id: Ia3dd0b4de1f1781d8369803aab8d280d75c867ce
Reviewed-on: https://gerrit.chromium.org/gerrit/31765
Commit-Ready: Andrew de los Reyes <adlr@chromium.org>
Reviewed-by: Andrew de los Reyes <adlr@chromium.org>
Tested-by: Andrew de los Reyes <adlr@chromium.org>
1 file changed