Don't clear state modifications on commit (#112)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/worldstate/DefaultMutableWorldState.java

@@ -390,10 +390,6 @@ public class DefaultMutableWorldState implements MutableWorldState {
 
         wrapped.accountStateTrie.put(updated.getAddressHash(), account);
       }
-
-      // After committing, clear data
-      deletedAccounts().clear();
-      updatedAccounts().clear();
     }
   }
 }