image.c: clear image variable

Not zeroing the image after talloc occasionally leads to a segfault because
the programme thinks it has a signature when in reality it just has a junk
pointer and segfaults.

Signed-off-by: James Bottomley <JBottomley@Parallels.com>

src/image.c

@@ -401,6 +401,7 @@ struct image *image_load(const char *filename)
 		return NULL;
 	}
 
+	memset(image, 0, sizeof(*image));
 	rc = fileio_read_file(image, filename, &image->buf, &image->size);
 	if (rc)
 		goto err;