Clean up sr-io (#3609)

* Move trait `Printable` into `sr-primitives`

* Cleanup runtime io trie_root interfaces

* Remove last generic bits from sr-io interface

* Fix srml-sudo after master merge

* Fix benchmarks

* Runtime bump

substrate/srml/system/src/lib.rs

@@ -118,10 +118,10 @@ use safe_mix::TripletMix;
 use codec::{Encode, Decode};
 
 #[cfg(any(feature = "std", test))]
-use runtime_io::{TestExternalities, Blake2Hasher};
+use runtime_io::TestExternalities;
 
 #[cfg(any(feature = "std", test))]
-use primitives::ChangesTrieConfiguration;
+use primitives::{ChangesTrieConfiguration, Blake2Hasher};
 
 pub mod offchain;
 
@@ -151,8 +151,7 @@ pub fn extrinsics_root<H: Hash, E: codec::Encode>(extrinsics: &[E]) -> H::Output
 
 /// Compute the trie root of a list of extrinsics.
 pub fn extrinsics_data_root<H: Hash>(xts: Vec<Vec<u8>>) -> H::Output {
-	let xts = xts.iter().map(Vec::as_slice).collect::<Vec<_>>();
-	H::ordered_trie_root(&xts)
+	H::ordered_trie_root(xts)
 }
 
 pub trait Trait: 'static + Eq + Clone {