Make sure no temp files get created from CoreSchema init

[vanstyn]

Need to check and make sure the CoreSchema init, which uses Schema::Loader during self-verification, isn't creating and leaving temp files on disk. I noticed earlier this might be happening, but then forgot about it until I was reminded by a recent PR/issue that was opened for dbic:

https://github.com/dbsrgits/dbix-class/pull/67

This is not the same issue as S::L, but it did remind me, and so I need to check on the deployment_statements call as well...