Address results of PVS-Studio static analysis

Couple are left un-addressed, see #958 for details.

include/internal/catch_message.h

@@ -49,7 +49,6 @@ namespace Catch {
     class ScopedMessage {
     public:
         ScopedMessage( MessageBuilder const& builder );
-        ScopedMessage( ScopedMessage const& other );
         ~ScopedMessage();
 
         MessageInfo m_info;