Correct pci resources log

In _report_final_resource_view() method, Nova will never record
"free pci" in log message because 'pci_devices' is not in dict 'resources'.

Closes-bug: #1314008

Change-Id: I90f1e3c624922c39e47f5e1fcccc7e33139d54e7
Add log translation hints.

Oslo would like to see hints like this in all of our code by the
end of juno. I'll slowly trickle the changes out over the
release.

Change-Id: I5aa89ec5e1abd7222967467261de9fecb3afa57b
Merge "Add log translation hints."
Merge "Correct pci resources log"