runtime: Remove obsolete GovernanceCurrency type.

runtime-modules/common/src/currency.rs

@@ -1,16 +1,5 @@
-use frame_support::traits::{Currency, LockableCurrency, ReservableCurrency};
 use sp_runtime::traits::Convert;
 
-pub trait GovernanceCurrency: frame_system::Trait + Sized {
-    type Currency: Currency<Self::AccountId>
-        + ReservableCurrency<Self::AccountId>
-        + LockableCurrency<Self::AccountId, Moment = Self::BlockNumber>;
-}
-
-pub type BalanceOf<T> = <<T as GovernanceCurrency>::Currency as Currency<
-    <T as frame_system::Trait>::AccountId,
->>::Balance;
-
 /// A structure that converts the currency type into a lossy u64
 /// And back from u128
 pub struct CurrencyToVoteHandler;

runtime/src/lib.rs

@@ -452,10 +452,6 @@ impl content_directory::Trait for Runtime {
     type IndividualEntitiesCreationLimit = IndividualEntitiesCreationLimit;
 }
 
-impl common::currency::GovernanceCurrency for Runtime {
-    type Currency = pallet_balances::Module<Self>;
-}
-
 // The referendum instance alias.
 pub type ReferendumInstance = referendum::Instance1;
 pub type ReferendumModule = referendum::Module<Runtime, ReferendumInstance>;