assign the vmod objects

... otherwise vcl_init fails with varnish-cache master and also
we would leak on vcl destroy.

src/vfp_brotli.c

@@ -673,6 +673,7 @@ vmod_encoder__init(VRT_CTX, struct vmod_brotli_encoder **encp,
 	settings->large_win = large_win;
 	settings->lgwin = lgwin;
 	enc->vfp = vfp;
+	*encp = enc;
 }
 
 /*
@@ -726,6 +727,7 @@ vmod_decoder__init(VRT_CTX, struct vmod_brotli_decoder **decp,
 	settings->which = DEC;
 	settings->large_win = large_win;
 	dec->vfp = vfp;
+	*decp = dec;
 }
 
 /*