Use mainline rust-postgres

[vorot93]

No description provided.

[ChristophWurst]

👍 since the fixes were merged upstream sfackler/rust-postgres#321

[ChristophWurst]

@vorot93 fyi, there are two warnings:

warning: unused import: `tokio_postgres::tls::Handshake`
  --> postgres/src/lib.rs:15:5
   |
15 | use tokio_postgres::tls::Handshake;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: #[warn(unused_imports)] on by default

warning: unused import: `std::fmt`
  --> postgres/src/lib.rs:17:5
   |
17 | use std::fmt;
   |     ^^^^^^^^

This also fixes compiler errors I get on the master branch.

[khuey]

Thank you. I reinstated the debug implementation for PostgresConnectionManager and fixed the warnings.