BUG/MINOR: quic: Fix memory leak in quic_deallocate_dghdlrs()

When deallocating the QUIC datagram handlers, the per-thread buffer
allocated inside quic_dghdlrs[i].buf.buffer was missing a free().
This led to a memory leak on exit or reload.

Fix this by freeing each thread buffer before releasing the main
quic_dghdlrs array.

src/proto_quic.c

@@ -625,8 +625,10 @@ static int quic_deallocate_dghdlrs(void)
 	int i;
 
 	if (quic_dghdlrs) {
-		for (i = 0; i < global.nbthread; ++i)
+		for (i = 0; i < global.nbthread; ++i) {
+			free(quic_dghdlrs[i].buf.buffer);
 			tasklet_free(quic_dghdlrs[i].task);
+		}
 		free(quic_dghdlrs);
 	}