Tip payment is a different withdraw reason. (#3937)

* Tip payment is a different withdraw reason.

* Bump runtime version.

* Test fix.

* Fix lock type

substrate/srml/contracts/src/exec.rs

@@ -642,7 +642,7 @@ fn transfer<'a, T: Trait, V: Vm<T>, L: Loader<T>>(
 	if would_create && value < ctx.config.existential_deposit {
 		return Err("value too low to create account");
 	}
-	T::Currency::ensure_can_withdraw(transactor, value, WithdrawReason::Transfer, new_from_balance)?;
+	T::Currency::ensure_can_withdraw(transactor, value, WithdrawReason::Transfer.into(), new_from_balance)?;
 
 	let new_to_balance = match to_balance.checked_add(&value) {
 		Some(b) => b,

substrate/srml/contracts/src/gas.rs

@@ -215,7 +215,7 @@ pub fn buy_gas<T: Trait>(
 	let imbalance = T::Currency::withdraw(
 		transactor,
 		cost,
-		WithdrawReason::Fee,
+		WithdrawReason::Fee.into(),
 		ExistenceRequirement::KeepAlive
 	)?;
 

substrate/srml/contracts/src/rent.rs

@@ -119,7 +119,7 @@ fn try_evict_or_and_pay_rent<T: Trait>(
 	let can_withdraw_rent = T::Currency::ensure_can_withdraw(
 		account,
 		dues_limited,
-		WithdrawReason::Fee,
+		WithdrawReason::Fee.into(),
 		balance.saturating_sub(dues_limited),
 	)
 	.is_ok();
@@ -129,7 +129,7 @@ fn try_evict_or_and_pay_rent<T: Trait>(
 		let imbalance = T::Currency::withdraw(
 			account,
 			dues_limited,
-			WithdrawReason::Fee,
+			WithdrawReason::Fee.into(),
 			ExistenceRequirement::KeepAlive,
 		)
 		.expect(