update nokogiri to v1.8.1
update nokogiri to v1.8.1

> libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a heap-based buffer over-read in the xmlDictAddString function i...

* http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-9050

fidor/fidor_api_demo,fidor/fidor_api_demo,fidor/fidor_api_demo