Use proper database configuration in snapshots. (#2052)

* use proper database config in snapshot service

* add snapshot path to parity directories struct

* fix RPC tests

ethcore/src/json_tests/chain.rs

@@ -58,12 +58,14 @@ pub fn json_chain_test(json_data: &[u8], era: ChainEra) -> Vec<String> {
 
 			let temp = RandomTempPath::new();
 			{
+				let db_config = DatabaseConfig::with_columns(::db::NUM_COLUMNS);
 				let client = Client::new(
 					ClientConfig::default(),
 					&spec,
 					temp.as_path(),
 					Arc::new(Miner::with_spec(&spec)),
-					IoChannel::disconnected()
+					IoChannel::disconnected(),
+					&db_config,
 				).unwrap();
 				for b in &blockchain.blocks_rlp() {
 					if Block::is_good(&b) {