Use module_name instead of repo_name

Some parts of the template require the repo_name to be present. This
commit replaces those usages with `oslo.{{cookiecutter.module_name}}` to
avoid requiring a repo_name to be specified.

Change-Id: Ie9d4720a8b8cb8d03e701640c58c346dcc688a71
Merge "Use module_name instead of repo_name"