A few client tools duplicate error messages already provided by libpq,
such as
pg_rewind: fatal: could not connect to server: could not connect to
server: No such file or directory
pg_basebackup: error: could not connect to server: could not connect to
server: No such file or directory
psql: error: could not connect to server: could not connect to server:
No such file or directory
The psql case is actually a regression introduced in PG12, but the other
two appear to be ancient.
Other client tools provide a different error message so in aggregate it
looks like this:
createdb: error: could not connect to database template1: could not
connect to server: No such file or directory
The attached patch removes the redundant message from the client tools.
I suppose it's a bit dubious because there is no guarantee what the
level of detail the message supplied by libpq has. But I think these
few cases are not particularly hard to keep in sync.
