Remove redundant imports

These became warnings in a recent nightly.

The TryFrom/TryInto imports were missed in
4089891f6c, but the rest are truly
redundant.

tokio-xmpp/src/client/bind.rs

@@ -1,5 +1,4 @@
 use futures::stream::StreamExt;
-use std::marker::Unpin;
 use tokio::io::{AsyncRead, AsyncWrite};
 use xmpp_parsers::bind::{BindQuery, BindResponse};
 use xmpp_parsers::iq::{Iq, IqType};