Improve error reporting in _get_my_ipv4_address()

Provide more detailed error reporting when we cannot figure out what the
IPv4 address of the server is.

Change-Id: Ifac8a2109ae00c9c2624e03725f41b6052890f77
Workflow documentation is now in infra-manual

Replace URLs for workflow documentation to appropriate parts of the
OpenStack Project Infrastructure Manual.

Change-Id: I888d3e2905755ae7833231363d5dab66799a4a48
Merge "Improve error reporting in _get_my_ipv4_address()"
Merge "Workflow documentation is now in infra-manual"