Add debug log for pci passthrough filter

Sometimes operator need information why the host doesn't pass
the check of scheduler, this patch adds information for pci
passthrough filter if it falied to pass check.

Change-Id: Ic8fe13174fda5c75ce95fc0b64391ae081b36c6d
Partial-Bug: #1301830
Merge "Add debug log for pci passthrough filter"