removed redundant unwraps (#935)

* removed redundant unwraps

* fixed compilation error, removed warnings

* fixed transaction queue merge conflict

* fixed failing ethminer doc test

ethcore/src/json_tests/chain.rs

@@ -53,7 +53,7 @@ pub fn json_chain_test(json_data: &[u8], era: ChainEra) -> Vec<String> {
 
 			let temp = RandomTempPath::new();
 			{
-				let client = Client::new(ClientConfig::default(), spec, temp.as_path(), IoChannel::disconnected()).unwrap();
+				let client = Client::new(ClientConfig::default(), spec, temp.as_path(), IoChannel::disconnected());
 				for b in &blockchain.blocks_rlp() {
 					if Block::is_good(&b) {
 						let _ = client.import_block(b.clone());

ethcore/src/json_tests/executive.rs

@@ -17,11 +17,9 @@
 use super::test_common::*;
 use state::*;
 use executive::*;
-use spec::*;
 use engine::*;
 use evm;
 use evm::{Schedule, Ext, Factory, VMType, ContractCreateResult, MessageCallResult};
-use ethereum;
 use externalities::*;
 use substate::*;
 use tests::helpers::*;