get pci device's numa_node info when collecting pci devices info

As a OpenStack installer, daisycloud-core project has a requirement: When there are more than one baremetal in a cluster which have the same hardware characteristic. Then only one of then need to be described and configured, and the others can be add into cluster without any human intervention. So daisycloud-core needs to collect some detail hardware info, such as numa info, from ironic-python-agent when using bifrost/ironic as the bare metal deployment tool.

When collecting pci devices info by using collect_pci_devices_info() function, only vendor and device info are collected. Now we need additional info about numa_node (such as /sys/bus/pci/devices/0000\:00\:03.0/numa_node) to help to compare if two baremetal are physically homogenious, thus can be quickly added into a OpenStack cluster by using existing homogenious nodes configuration.

I hope this small bp is just about to modify only one file (inspector.py) , and no need to update code of other part of ironic. But if it has to, then those things will be done all in this bp. Thanks.