Replace sys.exit by os._exit to be sure that the script stops on timeout immediately and does not produce false-positive results (usually it comes to WARNING).
Set status to unknown instead of critical for timeouts, authentication errors and such things as those issues are critical for the check itself but not for the service.
Andreas Gottwald sent a patch which fixes an issue, when the CIM element was a "NoneType" element but the plugin wanted to read a string from it.
Traceback (most recent call last):
File "./check_esxi_hardware.py", line 629, in <module>
verboseoutput(" Element Name = "+elementName)
TypeError: cannot concatenate 'str' and 'NoneType' objects
The change for the chassis serial number was already prepared a few months ago but I only found time today to do the merge and the release. Therefore adapting the date in history and version variable to today (20150109)
