[PATCH] Make "psql -1 < file.sql" work as with "-f"

Dear PostgreSQL developers,

Plese find attached a patch so that:

Make "psql -1 < file.sql" work as with "-f"

Make psql --single-transaction option work on a non-interactive
standard input as well, so that "psql -1 < input.sql" behaves as
"psql -1 -f input.sql".

This saner/less error-prone behavior was discussed in this thread back in
June:

http://archives.postgresql.org/pgsql-hackers/2012-06/msg00785.php

I have tested it manually and it works for me. I'm not sure this is the
best possible implementation, but it is a small diff one. I haven't found
a place in the regression tests where "psql" could be tested with
different options. Did I miss something?

--
Fabien.