delegate name attribute to parent_manager

[durandom]

when changing the name of a parent_manager, the name of the child manager is not updated.
because child_manager are mostly read-only, we just delegate the name display to the parent_manager

fixes https://bugzilla.redhat.com/show_bug.cgi?id=1464529

@hsong-rh could you 👍 the change on the storage manager?
@moolitayer could you 👍 the change on the monitoring manager?

@miq-bot assign @agrare
@miq-bot add_label bug

[miq-bot]

Checked commit durandom@742b0d6 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
4 files checked, 0 offenses detected
Everything looks fine. 🍰

[agrare]

👍 from me, will wait for feedback from others to merge

[moolitayer]

Should we also remove:
https://github.com/manageiq/manageiq/blob/70edcc40e631a9ef7ed2aaf79d09baf21e4b5726/app/models/mixins/has_network_manager_mixin.rb#L29
https://github.com/manageiq/manageiq/blob/62f873e33a5e82d65e0e281aadf912d313bae67d/app/models/mixins/has_monitoring_manager_mixin.rb#L10
...

[durandom]

@moolitayer here we validate the presence and uniqueness of the name. So, I'd keep setting the name there

[moolitayer]

LGTM 👍

[hsong-rh]

👍 from me