Silencing a false warning of gcc on Sid about uninitialized "image" variable

xorriso/iso_img.c

@@ -945,6 +945,7 @@ ex:;
 int Xorriso_get_volume(struct XorrisO *xorriso, IsoImage **volume,
                        int flag)
 {
+ *volume= NULL;
  if(xorriso->in_volset_handle==NULL) {
    if(flag & 1)
      return(0);