Track issue with ember data's createRecord when using async relationships

[raycohen]

This commit introduced a workaround to an issue described by the pull request below: https://github.com/yapplabs/glazier/commit/93ab922aa7ec886cd79a17c05ba7a20e57e74729

See: https://github.com/emberjs/data/pull/1459

Removing the workaround while leaving async: true results in records that are created on the client with createRecord being saved to the server but not showing up until the page is refreshed.