filter out page views with the same created_at ruby side
filter out page views with the same created_at ruby side

This avoids a sometimes-nasty query plan by removing request_id from the
order by clause, at the expense of selecting some duplicate rows and
having to query cassandra about them.

Also remove references to last_request_id since it's no longer used.

test plan: the page view cassandra migrator should still run, and not
process duplicate page view entries (as before).

refs #CNVS-868

Change-Id: I5933c695cc5f4c519f89362af315595221a70fdc
Reviewed-on: https://gerrit.instructure.com/15879
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Jacob Fugal <f862f167b85d41b225785c70d70808bc7337c1fe@instructure.com>
QA-Review: Brian Palmer <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@instructure.com>

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