Fix merge request diff api
Fix merge request diff api

Signed-off-by: Dmitriy Zaporozhets <be23d75b156792e5acab51b196a2deb155d35d6a@gmail.com>

allysonbarros/gitlabhq,stoplightio/gitlabhq,shinexiao/gitlabhq,shinexiao/gitlabhq,icedwater/gitlabhq,allysonbarros/gitlabhq,stoplightio/gitlabhq,darkrasid/gitlabhq,dreampet/gitlab,darkrasid/gitlabhq,stoplightio/gitlabhq,screenpages/gitlabhq,mr-dxdy/gitlabhq,t-zuehlsdorff/gitlabhq,LUMC/gitlabhq,iiet/iiet-git,darkrasid/gitlabhq,LUMC/gitlabhq,dplarson/gitlabhq,dplarson/gitlabhq,darkrasid/gitlabhq,shinexiao/gitlabhq,htve/GitlabForChinese,axilleas/gitlabhq,jirutka/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,dreampet/gitlab,LUMC/gitlabhq,SVArago/gitlabhq,screenpages/gitlabhq,daiyu/gitlab-zh,screenpages/gitlabhq,daiyu/gitlab-zh,openwide-java/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,jirutka/gitlabhq,daiyu/gitlab-zh,LUMC/gitlabhq,jirutka/gitlabhq,allysonbarros/gitlabhq,htve/GitlabForChinese,iiet/iiet-git,iiet/iiet-git,SVArago/gitlabhq,dplarson/gitlabhq,allysonbarros/gitlabhq,mr-dxdy/gitlabhq,openwide-java/gitlabhq,htve/GitlabForChinese,shinexiao/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,screenpages/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,axilleas/gitlabhq,SVArago/gitlabhq,axilleas/gitlabhq,icedwater/gitlabhq,dreampet/gitlab,SVArago/gitlabhq,htve/GitlabForChinese,mr-dxdy/gitlabhq,t-zuehlsdorff/gitlabhq,icedwater/gitlabhq,mr-dxdy/gitlabhq,iiet/iiet-git,mmkassem/gitlabhq,openwide-java/gitlabhq,openwide-java/gitlabhq,icedwater/gitlabhq,daiyu/gitlab-zh,mmkassem/gitlabhq,t-zuehlsdorff/gitlabhq