Fix FakeExtVM.

libethereum/ExtVM.h

@@ -70,7 +70,7 @@ public:
 	virtual u256 txCount(Address _a) override final { return m_s.transactionsFrom(_a); }
 
 	/// Does the account exist?
-	virtual bool exists(Address _a) { return m_s.addressInUse(_a); }
+	virtual bool exists(Address _a) override final { return m_s.addressInUse(_a); }
 
 	/// Suicide the associated contract to the given address.
 	virtual void suicide(Address _a) override final

test/vm.h

@@ -52,6 +52,7 @@ public:
 
 	virtual u256 store(u256 _n) override { return std::get<2>(addresses[myAddress])[_n]; }
 	virtual void setStore(u256 _n, u256 _v) override { std::get<2>(addresses[myAddress])[_n] = _v; }
+	virtual bool exists(Address _a) override { return !!addresses.count(_a); }
 	virtual u256 balance(Address _a) override { return std::get<0>(addresses[_a]); }
 	virtual void subBalance(u256 _a) override { std::get<0>(addresses[myAddress]) -= _a; }
 	virtual u256 txCount(Address _a) override { return std::get<1>(addresses[_a]); }