Fix cross-version compatibility checks of pg_verify_checksums
pg_verify_checksums performs a read of the control file, and the data it
fetches should be from a data folder compatible with the major version
of Postgres the binary has been compiled with, but we never actually
checked that compatibility.
Reported-by: Sergei Kornilov
Author: Michael Paquier
Reviewed-by: Sergei Kornilov
Discussion: https://postgr.es/m/
155231347133.16480.
11453587097036807558.pgcf@coridan.postgresql.org
Backpatch-through: 11