don't ref link to create new collab if it doesn't exist
don't ref link to create new collab if it doesn't exist

fixes #4989

Change-Id: I9fa7d7cfdf355fe0483f613f998a67cd53257c17
Reviewed-on: https://gerrit.instructure.com/6300
Tested-by: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@instructure.com>
Reviewed-by: Ryan Florence <2d8900489f91ac272fd9ce9d5789db6522668ca2@instructure.com>

venturehive/canvas-lms,usmschuck/canvas,leftplusrightllc/canvas-lms,Jyaasa/canvas-lms,Unow/canvas-lms,Rvor/canvas-lms,arrivu/qibla-ecampus,em2/canvas-lms,ShreniiNepal/shrenii_lmp,redconfetti/canvas-lms,snehakachroo1/LSI_replica,arrivu/jigsaw-lms,djbender/canvas-lms,dgynn/canvas-lms,narigone/canvas,arrivu/qibla-ecampus,roxolan/canvas-lms,greyhwndz/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,arrivu/hiring-site,instructure/canvas-lms,instructure/canvas-lms,icelab/canvas,arrivu/hoodemo,dgynn/canvas-lms,landonwilkins/canvas-lms,eCNAP/CANVAS,Jyaasa/canvas-lms,landonwilkins/canvas-lms,AndranikMarkosyan/lms,jay3126/canvas-lms,jay3126/canvas-lms,parbros/red-innovadores-lms,icelab/canvas,Unow/ins,shidao-fm/canvas-lms,skmezanul/canvas-lms,leftplusrightllc/canvas-lms,redconfetti/canvas-lms,wye0220/shindig-canvas,shidao-fm/canvas-lms,juoni/canvas-lms,samuels410/greatlakes-lms,venturehive/canvas-lms,ottenhoff/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,tgroshon/canvas-lms,sdeleon28/canvas-lms,redconfetti/canvas-lms,Unow/ins,matematikk-mooc/canvas-lms,loganrun/pincan,samuels410/greatlakes-lms,em2/canvas-lms,parbros/red-innovadores-lms,sdeleon28/canvas-lms,utkarshx/canvas-lms,gbleydon/canvas-lms,Rvor/canvas-lms,fronteerio/canvas-lms,ShreniiNepal/shrenii_lmp,AndranikMarkosyan/lms,antoniuslin/canvas-lms,va7map/canvas-lms,grahamb/canvas-lms,merichar/canvas-lms,SwinburneOnline/canvas-lms,Unow/canvas-lms,samuels410/greatlakes-lms,va7map/canvas-lms,eCNAP/CANVAS,jay3126/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,wrdsb/canvas-lms,nditech/red-innovadores-lms,fronteerio/canvas-lms,whalejasmine/canvas-lms,whalejasmine/canvas-lms,va7map/canvas-lms,em2/canvas-lms,usmschuck/canvas,snehakachroo1/LSI_replica,wimemx/Canvas,grahamb/canvas-lms,arrivu/hiring-site,sfu/canvas-lms,utkarshx/canvas-lms,AndranikMarkosyan/lms,ShreniiNepal/shrenii_lmp,matematikk-mooc/canvas-lms,juoni/canvas-lms,venturehive/canvas-lms,whalejasmine/canvas-lms,skmezanul/canvas-lms,shidao-fm/canvas-lms,dgynn/canvas-lms,rup/Tarrax,eCNAP/CANVAS,ankithbti/canvas_lms,matematikk-mooc/canvas-lms,nditech/red-innovadores-lms,jay3126/canvas-lms,efrj/canvas-lms,instructure/canvas-lms,ShreniiNepal/shrenii_lmp,greyhwndz/canvas-lms,ottenhoff/canvas-lms,efrj/canvas-lms,djbender/canvas-lms,greyhwndz/canvas-lms,samuels410/greatlakes-lms,faraazkhan/canvas,venturehive/canvas-lms,Unow/ins,arrivu/hiring-site,sli7246/canvas_branch,nditech/red-innovadores-lms,gbleydon/canvas-lms,kyroskoh/canvas-lms,fronteerio/canvas-lms,wye0220/shindig-canvas,arrivu/hoodemo,sfu/canvas-lms,faraazkhan/canvas,tgroshon/canvas-lms,wrdsb/canvas-lms,leftplusrightllc/canvas-lms,sfu/canvas-lms,greyhwndz/canvas-lms,usmschuck/canvas,arrivu/qibla-ecampus,efrj/canvas-lms,HotChalk/canvas-lms,narigone/canvas,rup/Tarrax,juoni/canvas-lms,rup/Tarrax,whalejasmine/canvas-lms,faraazkhan/canvas,sdeleon28/canvas-lms,utkarshx/canvas-lms,wrdsb/canvas-lms,merichar/canvas-lms,roxolan/canvas-lms,parbros/red-innovadores-lms,juoni/canvas-lms,wye0220/shindig-canvas,icelab/canvas,Rvor/canvas-lms,AndranikMarkosyan/lms,utkarshx/canvas-lms,instructure/canvas-lms,antoniuslin/canvas-lms,SwinburneOnline/canvas-lms,kyroskoh/canvas-lms,sli7246/canvas_branch,snehakachroo1/LSI_replica,sli7246/canvas_branch,fronteerio/canvas-lms,dgynn/canvas-lms,ankithbti/canvas_lms,tgroshon/canvas-lms,ankithbti/canvas_lms,usmschuck/canvas,sfu/canvas-lms,djbender/canvas-lms,kyroskoh/canvas-lms,skmezanul/canvas-lms,sdeleon28/canvas-lms,gbleydon/canvas-lms,snehakachroo1/LSI_replica,landonwilkins/canvas-lms,wrdsb/canvas-lms,wimemx/Canvas,merichar/canvas-lms,djbender/canvas-lms,Jyaasa/canvas-lms,arrivu/arrivu-lms,kyroskoh/canvas-lms,arrivu/hoodemo,efrj/canvas-lms,arrivu/arrivu-lms,Unow/canvas-lms,arrivu/arrivu-lms,loganrun/pincan,matematikk-mooc/canvas-lms,skmezanul/canvas-lms,va7map/canvas-lms,antoniuslin/canvas-lms,leftplusrightllc/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,wimemx/Canvas,antoniuslin/canvas-lms,instructure/canvas-lms,Rvor/canvas-lms,loganrun/pincan,roxolan/canvas-lms,shidao-fm/canvas-lms,HotChalk/canvas-lms,arrivu/jigsaw-lms,narigone/canvas,redconfetti/canvas-lms,HotChalk/canvas-lms,narigone/canvas,instructure/canvas-lms,tgroshon/canvas-lms,eCNAP/CANVAS,arrivu/jigsaw-lms,ottenhoff/canvas-lms,landonwilkins/canvas-lms,SwinburneOnline/canvas-lms,roxolan/canvas-lms,Jyaasa/canvas-lms,grahamb/canvas-lms,nditech/red-innovadores-lms