Removed other unused variables in CDC.cpp and HID.cpp

See #1877

cores/arduino/HID.cpp

@@ -511,8 +511,8 @@ void Keyboard_::releaseAll(void)
 size_t Keyboard_::write(uint8_t c)
 {	
 	uint8_t p = press(c);  // Keydown
-	uint8_t r = release(c);		// Keyup
-	return (p);					// just return the result of press() since release() almost always returns 1
+	release(c);            // Keyup
+	return p;              // just return the result of press() since release() almost always returns 1
 }
 
 #endif

cores/arduino/USBCore.cpp

@@ -274,7 +274,6 @@ int USB_Send(u8 ep, const void* d, int len)
 
 	int r = len;
 	const u8* data = (const u8*)d;
-	u8 zero = ep & TRANSFER_ZERO;
 	u8 timeout = 250;		// 250ms timeout on send? TODO
 	while (len)
 	{