fix assertion failure in vped_gzgz_init() because of GZIPBITS

waiting for the boc happened at the wrong place

***  v1   debug|Assert error in vped_gzgz_init(), foreign/cache_esi_deliver.c line 163:
***  v1   debug|  Condition(foo->start > 0 && foo->start < foo->olen * 8) not true.

src/vdp_pesi.c

@@ -2427,6 +2427,21 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 	if (boc == NULL && ObjGetLen(req->wrk, req->objcore) == 0)
 		goto clean; // XXX
 
+	/* XXX needed ??? */
+	i = ObjCheckFlag(req->wrk, req->objcore, OF_GZIPED);
+
+	if (parent->nexus.gzip.is && i && !(req->res_mode & RES_ESI)) {
+		/* OA_GZIPBITS are not valid until BOS_FINISHED */
+		if (boc != NULL)
+			ObjWaitState(req->objcore, BOS_FINISHED);
+
+		if (req->objcore->flags & OC_F_FAILED) {
+			/* No way of signalling errors in the middle of
+			   the ESI body. Omit this ESI fragment. */
+			goto clean; // XXX
+		}
+	}
+
 	if ((req->objcore->flags & OC_F_FINAL) != 0 &&
 	    !ObjHasAttr(req->wrk, req->objcore, OA_ESIDATA)) {
 		VSLdbg(req, "vped_deliver: T_FINAL");
@@ -2519,20 +2534,6 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 
 	VSLdbg(req, "vped_deliver: ESI");
 
-	/* XXX needed ??? */
-	i = ObjCheckFlag(req->wrk, req->objcore, OF_GZIPED);
-
-	if (parent->nexus.gzip.is && i && !(req->res_mode & RES_ESI)) {
-		/* OA_GZIPBITS are not valid until BOS_FINISHED */
-		if (boc != NULL)
-			ObjWaitState(req->objcore, BOS_FINISHED);
-
-		if (req->objcore->flags & OC_F_FAILED) {
-			/* No way of signalling errors in the middle of
-			   the ESI body. Omit this ESI fragment. */
-			goto clean; // XXX
-		}
-	}
 	VDP_Push(req, &VDP_pesi_buf, tree);
 	XXXAZ(push_vdps(req, &parent->nexus.gzip));
 	AN(parent);