vout_picture: set picture type to MEMORY_PICTURE

src/video_output/vout_pictures.c

@@ -1026,7 +1026,7 @@ picture_t *picture_New( vlc_fourcc_t i_chroma, int i_width, int i_height, int i_
         free( p_picture );
         return NULL;
     }
-
+    p_picture->i_type = MEMORY_PICTURE;
     p_picture->i_refcount = 1;
     p_picture->pf_release = PictureReleaseCallback;
     p_picture->i_status = RESERVED_PICTURE;