schema version compare -- only crr schema version matters

[tantaman]

schema version is used in two ways:

1. Determining if we need to automigrate
2. Determining if nodes can sync to one another

For (2), we only need to version the crr bits of the schema.
For (1), we need to version the entire schema.

Peers could diverge (esp in client-server setups) and have their own set of local-only tables. Given that, it'd be pretty important to bifurcate the version along crr vs not crr lines.