Remove unneeded Serde requirements (#1076)

* Remove superfluous serde requirements.

* Try to ensure hash is serde

* Fixups

* Building again

* Attempt to reenable Block (doesn't build)

* Fixes compilation for node cli

* Fixes test compilation

* Fix wasm

* Fix tests

* Remove unneeded changes

* Fix up comments

* Reenable some code

* Compile error when origin misused.

* Remove unnecessary includes of `serde_derive`

* Cleanups

substrate/srml/executive/src/lib.rs

@@ -18,10 +18,6 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(test)]
-#[macro_use]
-extern crate serde_derive;
-
 #[cfg(test)]
 #[macro_use]
 extern crate parity_codec_derive;
@@ -295,7 +291,7 @@ mod tests {
 	}
 
 	// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
-	#[derive(Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+	#[derive(Clone, Eq, PartialEq)]
 	pub struct Runtime;
 	impl system::Trait for Runtime {
 		type Origin = Origin;