BUG/MINOR: httpclient/lua: misplaced luaL_buffinit()

Some luaL_buffinit() call was done before the push of the variable name,
where it seems to work correctly with lua < 5.4.3, it brokes
systematically on this version.

This patch inverts the pushstring and the buffinit.
diff --git a/src/hlua.c b/src/hlua.c
index 435455b..e9d4391 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -7200,8 +7200,8 @@
 	/* we return a "res" object */
 	lua_newtable(L);
 
-	luaL_buffinit(L, &hlua_hc->b);
 	lua_pushstring(L, "body");
+	luaL_buffinit(L, &hlua_hc->b);
 
 	MAY_LJMP(hlua_yieldk(L, 0, 0, hlua_httpclient_rcv_yield, TICK_ETERNITY, 0));