libobs: Fix releasing filters on source destroy

I was iterating through the obs_source::filters array to remove filters,
but every time I removed a filter, it would remove itself from the
array, therefore it would end up skipping items in the array, therefore
leaving filters unreleased.  This just removes the first filter until
all filters have been removed.

libobs/obs-source.c

@@ -249,8 +249,8 @@ void obs_source_destroy(struct obs_source *source)
 	if (source->filter_parent)
 		obs_source_filter_remove(source->filter_parent, source);
 
-	for (i = 0; i < source->filters.num; i++)
-		obs_source_release(source->filters.array[i]);
+	while (source->filters.num)
+		obs_source_filter_remove(source, source->filters.array[0]);
 
 	for (i = 0; i < source->async_cache.num; i++)
 		obs_source_frame_destroy(source->async_cache.array[i].frame);