rose edit: ignore rose-meta.conf root level confs.

Instead of dying with a traceback.
Merge branch 'master' into 473.edit.meta.root-settings
Merge branch 'master' into 473.edit.meta.root-settings
Merge pull request #481 from matthewrmshin/473.edit.meta.root-settings

rose edit: ignore rose-meta.conf root level confs.