Give an error for old protocol version.
Special handling of error message to V2 client.
Add an IT for that.
Include bad message in failure report.
merge MMcM: Check for unsupported Postgres protocol version and give explicit error

Merge pull request #1030 from MMcM/sql-layer/pg-reject-old-ptcl-version
https://github.com/FoundationDB/sql-layer/pull/1030