[master] ce71896ae sess: Plug conceptual leak

[Dridi Boukelmoune]

commit ce71896ae353387d1da4088f5c6c3921d98b249a
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Tue Jul 13 07:52:15 2021 +0200

    sess: Plug conceptual leak
    
    It's harmless with a regular workspace, but technically we are leaving
    outstanding allocations in the workspace.

diff --git a/bin/varnishd/cache/cache_session.c b/bin/varnishd/cache/cache_session.c
index dbbce45d0..51d10b417 100644
--- a/bin/varnishd/cache/cache_session.c
+++ b/bin/varnishd/cache/cache_session.c
@@ -654,6 +654,7 @@ SES_Rel(struct sess *sp)
 	if (i)
 		return;
 	Lck_Delete(&sp->mtx);
+	WS_Rollback(sp->ws, 0);
 	MPL_Free(sp->pool->mpl_sess, sp);
 }