No "Factory error" splashscreen on ChromeOS VMs

If the HWID is invalid (for instance, "unknown") and the firmware ID is non-Chrome ("nonchrome") then assume that we're running in a VM and do not report a factory
error. A warning message is added to the log.

BUG=b:30155895

Review-Url: https://codereview.chromium.org/2187473006
Cr-Commit-Position: refs/heads/master@{#408870}
1 file changed