BUG/MINOR: sink: free the forwarding task on exit

ASAN reported a small leak of the sink's forwarding task on exit.

This should be backported as far as 2.2.

(cherry picked from commit 09727ee201211df47a3158334e73a8346f599716)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit c5a51631a90846551271eebfaba24f763d88c55e)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit f2433e9ac2e42bcc4185598221005fafa6b9577a)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit fd46ba034d2a1c7fbd3b0cbd1e1333a9bd223491)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/sink.c b/src/sink.c
index fbefbea..b7f111c 100644
--- a/src/sink.c
+++ b/src/sink.c
@@ -1289,6 +1289,7 @@
 		if (sink->type == SINK_TYPE_BUFFER)
 			ring_free(sink->ctx.ring);
 		LIST_DELETE(&sink->sink_list);
+		task_destroy(sink->forward_task);
 		free(sink->name);
 		free(sink->desc);
 		free(sink);