Fixed RasPi builds of unit tests.

On RasPi with gcc 4.8.2, the asserts wouldn't compile when tests were enabled.
Enforced the assumption that ASSERT code is generated only in Debug builds.

src/CompositeChat.cpp

@@ -284,7 +284,9 @@ cLogger::eLogLevel cCompositeChat::MessageTypeToLogLevel(eMessageType a_MessageT
 		case mtLeave:          return cLogger::llRegular;
 	}
 	ASSERT(!"Unhandled MessageType");
-	return cLogger::llError;
+	#ifndef __clang__
+		return cLogger::llError;
+	#endif
 }