fixed load image for OpenCV 3.0

AlexeyAB

2017-08-03 111b749d030b976758b2de337133d881fe47ffdc

fixed load image for OpenCV 3.0

 src/image.c

@@ -1305,9 +1305,15 @@
image load_image(char *filename, int w, int h, int c)
{
#ifdef OPENCV
    image out = load_image_cv(filename, c);

#ifndef CV_VERSION_EPOCH
    image out = load_image_stb(filename, c);    // OpenCV 3.x
#else
    image out = load_image_stb(filename, c);
    image out = load_image_cv(filename, c);     // OpenCV 2.4.x
#endif

#else
    image out = load_image_stb(filename, c);    // without OpenCV
#endif

    if((h && w) && (h != out.h || w != out.w)){