Revert "Lint for sum and product in consensus code (#2226)"

This reverts commit a3c482e.

Author: michaelsproul

consensus/state_processing/clippy.toml

@@ -1,5 +1,4 @@
 #![deny(clippy::integer_arithmetic)]
-#![deny(clippy::disallowed_method)]
 
 #[macro_use]
 mod macros;

consensus/state_processing/src/lib.rs

@@ -1,5 +1,4 @@
 #![allow(clippy::integer_arithmetic)]
-#![allow(clippy::disallowed_method)]
 
 use super::Error;
 use crate::{BeaconState, EthSpec, Hash256, Slot, Unsigned, Validator};

consensus/types/clippy.toml

@@ -4,7 +4,6 @@
 #![recursion_limit = "128"]
 // Clippy lint set up
 #![deny(clippy::integer_arithmetic)]
-#![deny(clippy::disallowed_method)]
 
 #[macro_use]
 extern crate lazy_static;