Fix error 500 when target is nil on todo list
Fix error 500 when target is nil on todo list

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