Show schema in COPY error CONTEXT strings

Use case: when running a process that populates many inherited
tables across schemas, having one fail gives the unhelpful
error message:

ERROR: invalid input syntax for integer: "abc"
CONTEXT: COPY foo, line 1, column a: "abc"

Unhelpful because "foo" does not uniquely identifies the table
or statement in question, which was actually: COPY alpha.foo FROM STDIN;
where 'alpha' was one of scores of schemas being populated. This
patch changes the output to:

ERROR: invalid input syntax for integer: "abc"
CONTEXT: COPY alpha.foo, line 1, column a: "abc"

I had to change the initial table in test/regress/sql/copy2.sql
from a temp table to a real table, as I could not find an easy
way to represent a wild card temp schema name inside of the
test/regres/expected/copy2.out file.

--
Greg Sabino Mullane greg(at)endpoint(dot)com
End Point Corporation
PGP Key: 0x14964AC8