It's Clippy time (#3806)

Fix some Clippy issues

substrate/core/consensus/babe/primitives/src/digest.rs

@@ -91,7 +91,7 @@ impl BabePreDigest {
 }
 
 /// The prefix used by BABE for its VRF keys.
-pub const BABE_VRF_PREFIX: &'static [u8] = b"substrate-babe-vrf";
+pub const BABE_VRF_PREFIX: &[u8] = b"substrate-babe-vrf";
 
 /// A raw version of `BabePreDigest`, usable on `no_std`.
 #[derive(Copy, Clone, Encode, Decode)]

substrate/core/consensus/babe/src/aux_schema.rs

@@ -38,7 +38,7 @@ fn load_decode<B, T>(backend: &B, key: &[u8]) -> ClientResult<Option<T>>
 		T: Decode,
 {
 	let corrupt = |e: codec::Error| {
-		ClientError::Backend(format!("BABE DB is corrupted. Decode error: {}", e.what())).into()
+		ClientError::Backend(format!("BABE DB is corrupted. Decode error: {}", e.what()))
 	};
 	match backend.get_aux(key)? {
 		None => Ok(None),