srml-contract: Fix Gas type to u64 (#2944)

* srml-contract: Move gas costs from Config to Schedule.

* srml-contract: Define Gas units fixed as u64.

This removes Gas as a configurable type on the contracts Trait.

* Bump node runtime spec/impl versions.

substrate/srml/contracts/src/tests.rs

@@ -93,7 +93,6 @@ impl timestamp::Trait for Test {
 impl Trait for Test {
 	type Currency = Balances;
 	type Call = Call;
-	type Gas = u64;
 	type DetermineContractAddress = DummyContractAddressFor;
 	type Event = MetaEvent;
 	type ComputeDispatchFee = DummyComputeDispatchFee;
@@ -215,8 +214,6 @@ impl ExtBuilder {
 				transfer_fee: self.transfer_fee,
 				creation_fee: self.creation_fee,
 				contract_fee: 21,
-				call_base_fee: 135,
-				create_base_fee: 175,
 				gas_price: self.gas_price,
 				max_depth: 100,
 				block_gas_limit: self.block_gas_limit,