add the canvas revision to error tags
add the canvas revision to error tags

test plan: Create a VERSION file in Canvas root dir with contents
"MyVerison", enable Sentry and record an error, the error should have a
canvas revision tag with value "MyVersion".

Change-Id: I4a588b9bbd2c76e4da90e79e121ff5a436d1e404
Reviewed-on: https://gerrit.instructure.com/54448
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Tested-by: Jenkins
QA-Review: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>
Product-Review: Brian Palmer <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@instructure.com>

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