fixed a typo in README: because of various coherent limitations in ngx_eval, thanks yanfeng.
fixed a typo in README: because of various coherent limitations in ngx_eval, thanks yanfeng.

openresty/nginx-eval-module,openresty/nginx-eval-module,guanhui07/nginx-eval-module,guanhui07/nginx-eval-module,guanhui07/nginx-eval-module,openresty/nginx-eval-module