add a random element to the sleep delay when job workers go idle
add a random element to the sleep delay when job workers go idle

Change-Id: Ic1ed3e555528af06764172e4c4ab7632d5839768
Reviewed-on: https://gerrit.instructure.com/11415
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Reviewed-by: Zach Wily <9de8c4480303b5335cd2a33eefe814615ba3612a@instructure.com>
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>

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