Fixes for Rust updates

lib.rs

@@ -447,7 +447,7 @@ impl InnerPostgresConnection {
                         payload: payload
                     }),
                 ParameterStatus { parameter, value } =>
-                    debug!("Parameter %s = %s", parameter, value),
+                    debug!("Parameter {} = {}", parameter, value),
                 msg => return msg
             }
         }

pool.rs

@@ -65,7 +65,7 @@ impl PostgresConnectionPool {
     pub fn new(url: &str, pool_size: uint) -> PostgresConnectionPool {
         match PostgresConnectionPool::try_new(url, pool_size) {
             Ok(pool) => pool,
-            Err(err) => fail!("Unable to initialize pool: %s", err.to_str())
+            Err(err) => fail!("Unable to initialize pool: {}", err.to_str())
         }
     }
 

tests.rs

@@ -59,7 +59,7 @@ fn test_prepare_err() {
     let conn = PostgresConnection::connect("postgres://postgres@localhost");
     match conn.try_prepare("invalid sql statment") {
         Err(PostgresDbError { code: SyntaxError, position: Some(Position(1)), _ }) => (),
-        resp => fail!("Unexpected result %?", resp)
+        resp => fail!("Unexpected result {:?}", resp)
     }
 }