Make postgresql.version a bit more flexible.
Make postgresql.version a bit more flexible.

Prior, split would error out if a version string with more than three version
fields was given. This can be troublesome for using the parser with versions
given by "non-pg" servers. So, make it more flexible, but guarantee three
version fields and two state fields.

Nicely, this ended up simplifying split and join.

python-postgres/fe,python-postgres/fe