unsupported WiredTiger file version should be added here and call setWtIncompatible

Consider having Version incompatibility detected also setWtIncompatible.

New description:
See how MongoDB and WT can cooperate to better express error cases on wiredtiger_open.

MongoDB behaviors today that can hopefully be simplified:

• MongoDB tries calling wiredtiger_open with a specific order of "compatibility versions" to learn the journal files WT discovered at startup.
  • Having a way to do this in one call would be great.
  • If multiple calls is still required, consider having a better way to suppress repeated compatibility error messages.
  • This line specifically is for WT refusing to startup on 4.0 or earlier data files.
• Knowing whether WT has modified data files.
  • When MongoDB is running with --repair it first creates a "repair lock file". That lock file can be safely removed after repair completes.
  • However, it's typical that newer MongoDB versions can be used to repair older data (to help lessen the burden of backporting). It can be unclear if a wiredtiger_open with salvage fails because data was corrupted, or if WT refused to look at the data files because of a versioning error (e.g: 4.4 on 4.0 data files) that's outside of any compatibility constraint.