fixed some more MSVC2010 warnings

samples/cpp/segment_objects.cpp

@@ -88,7 +88,7 @@ int main(int argc, char** argv)
         refineSegments(tmp_frame, bgmask, out_frame);
         imshow("video", tmp_frame);
         imshow("segmented", out_frame);
-        char keycode = waitKey(30);
+        int keycode = waitKey(30);
         if( keycode == 27 )
             break;
         if( keycode == ' ' )