ember-data 2.13+ throws error when booting ember-engines

[rwjblue]

The deprecations added as part of #4657 are written in a way that assumes the argument passed into the instance-initializer has an application property. This is true for normal applications, but is not true for engines (which still run our instance-initializers).

Specifically [this line] errors (because application.application is null):

  deprecateOldEmberDataInitializers(application.application.constructor.initializers);

[rwjblue]

I'm looking at fixing now...

[rwjblue]

Submitted PR's to fix ( #4969 and #4970).

[sly7-7]

Likely fixed 😄 Thanks @rwjblue