CommandLineArguments: Push the string back, not its C string

Change-Id: I2f02cf1c150019ecef628a322824a52c86c25431

CommandLineArguments.cxx

@@ -309,7 +309,7 @@ int CommandLineArguments::Parse()
       else if ( this->StoreUnusedArgumentsFlag )
         {
         CommandLineArguments_DEBUG("Store unused argument " << arg);
-        this->Internals->UnusedArguments.push_back(arg.c_str());
+        this->Internals->UnusedArguments.push_back(arg);
         }
       else
         {