Update CHANGELOG.md for 9.1.4
Update CHANGELOG.md for 9.1.4

[ci skip]
mmkassem/gitlabhq,axilleas/gitlabhq,t-zuehlsdorff/gitlabhq,dplarson/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,dplarson/gitlabhq,dreampet/gitlab,iiet/iiet-git,mmkassem/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,t-zuehlsdorff/gitlabhq,stoplightio/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,stoplightio/gitlabhq,jirutka/gitlabhq,dplarson/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,jirutka/gitlabhq,iiet/iiet-git,dplarson/gitlabhq,jirutka/gitlabhq,dreampet/gitlab,t-zuehlsdorff/gitlabhq,dreampet/gitlab,iiet/iiet-git