fixes for compiling libevm/VM.cpp with gcc

libevm/VM.cpp

@@ -25,7 +25,7 @@
 using namespace dev;
 using namespace dev::eth;
 
-void VM::reset(u256 _gas)
+void VM::reset(u256 _gas) noexcept
 {
 	VMFace::reset(_gas);
 	m_curPC = 0;

libevm/VM.h

@@ -52,10 +52,11 @@ public:
 	bytes const& memory() const { return m_temp; }
 	u256s const& stack() const { return m_stack; }
 
-private:
 	friend VMFace;
 	explicit VM(u256 _gas = 0): VMFace(_gas) {}
 
+private:
+
 	template <class Ext>
 	bytesConstRef go(Ext& _ext, OnOpFunc const& _onOp, uint64_t _steps);