postgres sudden change needs better support

[Jonathan Walther <krooger@debian.org>]

Between 6.5.1 and 6.5.3, Postgres now expects to find the databases in
/var/lib/postgres instead of /var/postgres.  I applaud this move, but it
would be nice if it was a little better supported.  In setups where
/var/postgres exists, and /var/lib/postgres does NOT, and the person chooses
to accept the maintainers version of the postmaster.init file, it would be
very nice if it would just move the one directory over to become the other.

I can see this gotcha getting a lot of users;  I was puzzled for a while why
my "Database does not exist" and why "Not a valid user" messages were coming
up at me.

Anyhow, I got it all working now, but if this could be fixed for future
upgraders, that would be nice.  thanks.  (Oliver, I know you're reading this
;)

Jonathan