Try to cover more cases about receivers of pipeline notifications
Try to cover more cases about receivers of pipeline notifications

Feedback:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6342#note_17981421

daiyu/gitlab-zh,LUMC/gitlabhq,mmkassem/gitlabhq,daiyu/gitlab-zh,t-zuehlsdorff/gitlabhq,LUMC/gitlabhq,darkrasid/gitlabhq,mmkassem/gitlabhq,darkrasid/gitlabhq,LUMC/gitlabhq,openwide-java/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,iiet/iiet-git,LUMC/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,stoplightio/gitlabhq,dplarson/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,darkrasid/gitlabhq,jirutka/gitlabhq,openwide-java/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,htve/GitlabForChinese,t-zuehlsdorff/gitlabhq,dplarson/gitlabhq,htve/GitlabForChinese,axilleas/gitlabhq,openwide-java/gitlabhq,daiyu/gitlab-zh,iiet/iiet-git,mmkassem/gitlabhq,mmkassem/gitlabhq,dreampet/gitlab,t-zuehlsdorff/gitlabhq,openwide-java/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,jirutka/gitlabhq,dplarson/gitlabhq,dplarson/gitlabhq,htve/GitlabForChinese,stoplightio/gitlabhq,dreampet/gitlab,daiyu/gitlab-zh,iiet/iiet-git,htve/GitlabForChinese,darkrasid/gitlabhq