Fix the VBE/VCL reference count anomaly

bin/varnishd/cache_backend.c

@@ -479,7 +479,7 @@ vdi_simple_fini(const struct director *d)
 	CAST_OBJ_NOTNULL(vs, d->priv, VDI_SIMPLE_MAGIC);
 
 	VBP_Stop(vs->backend, vs->vrt->probe);
-	VBE_DropRef(vs->backend);
+	VBE_DropRefVcl(vs->backend);
 	free(vs->dir.vcl_name);
 	vs->dir.magic = 0;
 	FREE_OBJ(vs);

bin/varnishd/cache_backend.h

@@ -143,7 +143,7 @@ struct backend *vdi_get_backend_if_simple(const struct director *d);
 /* cache_backend_cfg.c */
 extern struct lock VBE_mtx;
 void VBE_DropRefConn(struct backend *);
-void VBE_DropRef(struct backend *);
+void VBE_DropRefVcl(struct backend *);
 void VBE_DropRefLocked(struct backend *b);
 
 /* cache_backend_poll.c */

bin/varnishd/cache_backend_cfg.c

@@ -106,7 +106,6 @@ VBE_DropRefLocked(struct backend *b)
 	assert(b->refcount > 0);
 
 	i = --b->refcount;
-	b->vsc->vcls--;
 	Lck_Unlock(&b->mtx);
 	if (i > 0)
 		return;
@@ -125,12 +124,13 @@ VBE_DropRefLocked(struct backend *b)
 }
 
 void
-VBE_DropRef(struct backend *b)
+VBE_DropRefVcl(struct backend *b)
 {
 
 	CHECK_OBJ_NOTNULL(b, BACKEND_MAGIC);
 
 	Lck_Lock(&b->mtx);
+	b->vsc->vcls--;
 	VBE_DropRefLocked(b);
 }