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

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