Update QA Nokogiri to 1.8.1
Update QA Nokogiri to 1.8.1

Resolves three security advisories from bundle-audit

dreampet/gitlab,axilleas/gitlabhq,mmkassem/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,iiet/iiet-git,dreampet/gitlab,dreampet/gitlab,stoplightio/gitlabhq,mmkassem/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,jirutka/gitlabhq,iiet/iiet-git,jirutka/gitlabhq,iiet/iiet-git,jirutka/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,mmkassem/gitlabhq,dreampet/gitlab,stoplightio/gitlabhq,axilleas/gitlabhq