Only update the active_vcl on successful VCL compiles

bin/varnishd/mgt/mgt_vcl.c

@@ -207,8 +207,6 @@ mgt_vcl_add(const char *name, const char *state)
 	if (vp->state != VCL_STATE_COLD)
 		vp->warm = 1;
 
-	if (active_vcl == NULL)
-		active_vcl = vp;
 	VTAILQ_INSERT_TAIL(&vclhead, vp, list);
 	return (vp);
 }
@@ -353,6 +351,9 @@ mgt_new_vcl(struct cli *cli, const char *vclname, const char *vclsrc,
 	AZ(C_flag);
 	vp->fname = lib;
 
+	if (active_vcl == NULL)
+		active_vcl = vp;
+
 	if (child_pid < 0)
 		return;