orm: Fix MySQL occasional "Commands OOS" error

Under certain intermittent circumstances (usually a significant number of ORM queries), the ORM will trigger a MySQL error:
```
Commands out of sync; you can't run this command now
```
Usually this MySQL error is related to buffered versus unbuffered queries. However, the ORM already uses buffered queries (MySQL calls it "store_result"). In this case, it appears there is some sort of race between fetching the result metadata before configuring the statement for buffering. (By "race" I mean that the error is not reliably triggered).

This patch seems to fix the issue by configuring buffering before fetching result metadata — necessary to configure the fetching (output) phase of the statement.