BUG/MINOR: lua/filters: Return right code when txn:done() is called

txn functions can now be called from an action or a filter context. Thus the
return code must be adapted depending on this context. From an action, act.ABORT
is returned. From a filter, -1 is returned. It is the filter error code.

This bug only affects 2.5-dev. No backport needed.

src/hlua.c

@@ -7482,6 +7482,9 @@ __LJMP static int hlua_txn_done(lua_State *L)
 	if (!(s->flags & SF_FINST_MASK))
 		s->flags |= finst;
 
+	if ((htxn->flags & HLUA_TXN_CTX_MASK) == HLUA_TXN_FLT_CTX)
+		lua_pushinteger(L, -1);
+	else
 		lua_pushinteger(L, ACT_RET_ABRT);
 	WILL_LJMP(hlua_done(L));
 	return 0;