Query metadata is not passed through for update/delete queries.

[avolokhov]

When I perform update/delete queries in psql console, it returns me a number of affected rows:

test=> CREATE TABLE test_table(pk int PRIMARY KEY);
CREATE TABLE
test=> INSERT INTO test_table VALUES(1);
INSERT 0 1
test=> DELETE FROM test_table;
DELETE 1
test=> DELETE FROM test_table;
DELETE 0

PostgressConnection's api is responding with a list of database rows query(_ string: String, _ binds: [PostgresData] = []) -> EventLoopFuture<[PostgresRow]> and don't have this information.