Merge pull request #6720 from paritytech/kvdb_split

separated kvdb into 3 crates: kvdb, kvdb-memorydb && kvdb-rocksdb

ethcore/src/spec/spec.rs

@@ -672,13 +672,13 @@ impl Spec {
 	pub fn genesis_epoch_data(&self) -> Result<Vec<u8>, String> {
 		use transaction::{Action, Transaction};
 		use util::journaldb;
-		use kvdb;
+		use kvdb_memorydb;
 
 		let genesis = self.genesis_header();
 
 		let factories = Default::default();
 		let mut db = journaldb::new(
-			Arc::new(kvdb::in_memory(0)),
+			Arc::new(kvdb_memorydb::create(0)),
 			journaldb::Algorithm::Archive,
 			None,
 		);