Closed a memory leak with unreleased IsoImage in boot image inquiry

xorriso/xorrisoburn.c

@@ -4031,9 +4031,12 @@ no_boot:;
    }
    return(ret);
  }
+ /* Important: no return before iso_image_unref(image); */
 
  /* Using the nodes with extreme care . They might be deleted meanwhile. */
  ret= iso_image_get_boot_image(image, &bootimg, &bootimg_node, &bootcat_node);
+ iso_image_unref(image);
+ image= NULL;
  if(ret != 1)
    goto no_boot;
  ret= Xorriso_path_from_node(xorriso, NULL, xorriso->loaded_boot_bin_lba,