Ember3 is more picky about having a container being destroyed and it's easier to cause exceptions, especially in tests.
This fix has been initially created for an exception occuring in tests when running discourse-code-review and discourse-polls tests at the same time. `getCurrentUser` method body was failing as the container was destroyed.
Original stacktrace:
```
"Error: Assertion Failed: expected container not to be destroyed
at new EmberError (ember:2929:31)
at assert (ember:1793:23)
at Container.lookup (ember:17736:64)
at PluginApi.getCurrentUser (discourse/lib/plugin-api:56:31)
at allowUser (javascripts/discourse/initializers/init-code-review:38:29)
at eval (javascripts/discourse/initializers/init-code-review:78:11)
at eval (select-kit/mixins/plugin-api:86:19)
at Array.forEach (<anonymous>)
at eval (select-kit/mixins/plugin-api:85:44)
at Array.forEach (<anonymous>)"
```
Joffrey JAFFEUX
0d0303e7ea