cleanup local_filename from attachments
cleanup local_filename from attachments

it was removed

closes CNVS-21881

test plan
 - db:migrate should work

Change-Id: I9cfaa229babb2bbeb1e4c9d431308863ecf972ba
Reviewed-on: https://gerrit.instructure.com/58403
Product-Review: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>
QA-Review: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>
Tested-by: Jenkins
Reviewed-by: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>

tgroshon/canvas-lms,grahamb/canvas-lms,sdeleon28/canvas-lms,instructure/canvas-lms,redconfetti/canvas-lms,eCNAP/CANVAS,dgynn/canvas-lms,AndranikMarkosyan/lms,greyhwndz/canvas-lms,venturehive/canvas-lms,Rvor/canvas-lms,sdeleon28/canvas-lms,HotChalk/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,roxolan/canvas-lms,whalejasmine/canvas-lms,leftplusrightllc/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,AndranikMarkosyan/lms,sfu/canvas-lms,juoni/canvas-lms,eCNAP/CANVAS,HotChalk/canvas-lms,dgynn/canvas-lms,Jyaasa/canvas-lms,narigone/canvas,juoni/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,roxolan/canvas-lms,tgroshon/canvas-lms,jay3126/canvas-lms,djbender/canvas-lms,whalejasmine/canvas-lms,leftplusrightllc/canvas-lms,narigone/canvas,snehakachroo1/LSI_replica,snehakachroo1/LSI_replica,Jyaasa/canvas-lms,utkarshx/canvas-lms,narigone/canvas,dgynn/canvas-lms,roxolan/canvas-lms,AndranikMarkosyan/lms,kyroskoh/canvas-lms,djbender/canvas-lms,jay3126/canvas-lms,sfu/canvas-lms,sdeleon28/canvas-lms,djbender/canvas-lms,Rvor/canvas-lms,dgynn/canvas-lms,SwinburneOnline/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,skmezanul/canvas-lms,utkarshx/canvas-lms,matematikk-mooc/canvas-lms,fronteerio/canvas-lms,efrj/canvas-lms,whalejasmine/canvas-lms,utkarshx/canvas-lms,AndranikMarkosyan/lms,venturehive/canvas-lms,tgroshon/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms,Rvor/canvas-lms,sfu/canvas-lms,narigone/canvas,redconfetti/canvas-lms,sfu/canvas-lms,utkarshx/canvas-lms,efrj/canvas-lms,matematikk-mooc/canvas-lms,snehakachroo1/LSI_replica,kyroskoh/canvas-lms,instructure/canvas-lms,snehakachroo1/LSI_replica,fronteerio/canvas-lms,matematikk-mooc/canvas-lms,venturehive/canvas-lms,fronteerio/canvas-lms,efrj/canvas-lms,redconfetti/canvas-lms,antoniuslin/canvas-lms,tgroshon/canvas-lms,roxolan/canvas-lms,greyhwndz/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,antoniuslin/canvas-lms,Jyaasa/canvas-lms,SwinburneOnline/canvas-lms,kyroskoh/canvas-lms,skmezanul/canvas-lms,Rvor/canvas-lms,instructure/canvas-lms,jay3126/canvas-lms,fronteerio/canvas-lms,greyhwndz/canvas-lms,grahamb/canvas-lms,juoni/canvas-lms,HotChalk/canvas-lms,leftplusrightllc/canvas-lms,eCNAP/CANVAS,kyroskoh/canvas-lms,efrj/canvas-lms,leftplusrightllc/canvas-lms,antoniuslin/canvas-lms,sdeleon28/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,greyhwndz/canvas-lms,sfu/canvas-lms,jay3126/canvas-lms,skmezanul/canvas-lms,eCNAP/CANVAS,Jyaasa/canvas-lms,whalejasmine/canvas-lms,skmezanul/canvas-lms,sfu/canvas-lms,antoniuslin/canvas-lms,juoni/canvas-lms,matematikk-mooc/canvas-lms