allow disabling mail from outgoing_mail.yml
allow disabling mail from outgoing_mail.yml

test plan:
 * set perform_deliveries: false in outgoing_mail.yml
 * verify outgoing mail no longer happens, but you don't get a ton
   of error_reports for failed deliveries

Change-Id: I18b6cacc8fc7e79c60969728d5caf0a06caaf91a
Reviewed-on: https://gerrit.instructure.com/9338
Tested-by: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@instructure.com>
Reviewed-by: Brian Palmer <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@instructure.com>

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