Fix several memory leaks

* src/event.c: expose_root: region is not freed
* backend/xrender/xrender.c:
    * bind_pixmap: the reply `r` is not freed
    * blur: reg_op_resized is not freed

Spotted-by: Samuel Hand <samuel.d.hand@gmail.com>
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/xrender/xrender.c

@@ -168,6 +168,7 @@ static bool blur(backend_t *backend_data, double opacity, void *ctx_,
 	if (!tmp_picture[0] || !tmp_picture[1]) {
 		log_error("Failed to build intermediate Picture.");
 		pixman_region32_fini(&reg_op);
+		pixman_region32_fini(&reg_op_resized);
 		return false;
 	}
 
@@ -244,6 +245,7 @@ static bool blur(backend_t *backend_data, double opacity, void *ctx_,
 	xcb_render_free_picture(c, tmp_picture[0]);
 	xcb_render_free_picture(c, tmp_picture[1]);
 	pixman_region32_fini(&reg_op);
+	pixman_region32_fini(&reg_op_resized);
 	return true;
 }
 
@@ -268,6 +270,8 @@ bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool
 	    x_create_picture_with_visual_and_pixmap(base->c, fmt.visual, pixmap, 0, NULL);
 	img->owned = owned;
 	img->visual = fmt.visual;
+	free(r);
+
 	if (img->pict == XCB_NONE) {
 		free(img);
 		return NULL;

src/event.c

@@ -411,6 +411,7 @@ static inline void expose_root(session_t *ps, const rect_t *rects, int nrects) {
 	region_t region;
 	pixman_region32_init_rects(&region, rects, nrects);
 	add_damage(ps, &region);
+	pixman_region32_fini(&region);
 }
 
 static inline void ev_expose(session_t *ps, xcb_expose_event_t *ev) {