fix error handle in callback with lua_pcall according to https://www.lua.org/manual/5.1/manual.html#lua_pcall, errfunc cannot be a pseudo-index.
fix error handle in callback with lua_pcall
according to https://www.lua.org/manual/5.1/manual.html#lua_pcall, errfunc cannot be a pseudo-index.

joerg-krause/luv,luvit/luv,zhaozg/luv,luvit/luv,joerg-krause/luv,zhaozg/luv