Improve baremetal driver error handling

Several improvements to baremetal driver are implemented in this patch.
There is now significantly more error handling during spawn().

It also includes an addition to nova/tests/utils.py to provide
additional sample information from get_test_network_info().

blueprint general-bare-metal-provisioning-framework

Change-Id: I65d93051d7fcfd79f4d24d4ddb62fb1a55bee646
Merge "Improve baremetal driver error handling"