Remove private verify readonly attr method
Remove private verify readonly attr method

This method was added to be shared between update_attribute and
update_column in 50725cec397d4fa0ecf1dda4e6ae845a993f1ba7, but since
update_attribute was removed, and update_column has changed to delegate
to update_columns, the method is not used anywhere anymore.

Also remove "key.to_s" conversion when raising readonly error, since
the key is being interpolated.

stefanmb/rails,yawboakye/rails,notapatch/rails,hanystudy/rails,Envek/rails,sergey-alekseev/rails,betesh/rails,georgeclaghorn/rails,starknx/rails,arjes/rails,mohitnatoo/rails,kmcphillips/rails,kddeisz/rails,rails/rails,esparta/rails,travisofthenorth/rails,richseviora/rails,yahonda/rails,mijoharas/rails,bogdanvlviv/rails,printercu/rails,prathamesh-sonpatki/rails,elfassy/rails,MSP-Greg/rails,iainbeeston/rails,betesh/rails,rossta/rails,flanger001/rails,notapatch/rails,palkan/rails,mtsmfm/railstest,gfvcastro/rails,printercu/rails,lcreid/rails,travisofthenorth/rails,koic/rails,mtsmfm/rails,Stellenticket/rails,stefanmb/rails,shioyama/rails,sealocal/rails,deraru/rails,mijoharas/rails,yahonda/rails,yasslab/railsguides.jp,sealocal/rails,Envek/rails,baerjam/rails,kirs/rails-1,matrinox/rails,BlakeWilliams/rails,schuetzm/rails,eileencodes/rails,schuetzm/rails,ledestin/rails,jeremy/rails,prathamesh-sonpatki/rails,Envek/rails,bolek/rails,kmcphillips/rails,Vasfed/rails,felipecvo/rails,mtsmfm/railstest,palkan/rails,shioyama/rails,kmayer/rails,Vasfed/rails,tjschuck/rails,tijwelch/rails,kmcphillips/rails,mijoharas/rails,kmayer/rails,kddeisz/rails,mechanicles/rails,alecspopa/rails,starknx/rails,printercu/rails,pschambacher/rails,BlakeWilliams/rails,brchristian/rails,kmayer/rails,aditya-kapoor/rails,voray/rails,lucasmazza/rails,joonyou/rails,mohitnatoo/rails,prathamesh-sonpatki/rails,kachick/rails,travisofthenorth/rails,odedniv/rails,ledestin/rails,mohitnatoo/rails,georgeclaghorn/rails,eileencodes/rails,assain/rails,iainbeeston/rails,yawboakye/rails,voray/rails,odedniv/rails,BlakeWilliams/rails,vassilevsky/rails,illacceptanything/illacceptanything,kachick/rails,yhirano55/rails,felipecvo/rails,tjschuck/rails,koic/rails,fabianoleittes/rails,samphilipd/rails,gauravtiwari/rails,pschambacher/rails,matrinox/rails,pvalena/rails,88rabbit/newRails,esparta/rails,gfvcastro/rails,iainbeeston/rails,repinel/rails,vipulnsward/rails,kaspth/rails,repinel/rails,illacceptanything/illacceptanything,kenta-s/rails,rbhitchcock/rails,tgxworld/rails,rbhitchcock/rails,mathieujobin/reduced-rails-for-travis,baerjam/rails,baerjam/rails,joonyou/rails,lcreid/rails,deraru/rails,Stellenticket/rails,vassilevsky/rails,schuetzm/rails,xlymian/rails,illacceptanything/illacceptanything,pvalena/rails,MichaelSp/rails,gcourtemanche/rails,felipecvo/rails,arunagw/rails,riseshia/railsguides.kr,iainbeeston/rails,utilum/rails,BlakeWilliams/rails,kirs/rails-1,arunagw/rails,baerjam/rails,vassilevsky/rails,jeremy/rails,illacceptanything/illacceptanything,jeremy/rails,assain/rails,gcourtemanche/rails,ngpestelos/rails,lcreid/rails,travisofthenorth/rails,starknx/rails,yalab/rails,brchristian/rails,kaspth/rails,Erol/rails,deraru/rails,utilum/rails,Edouard-chin/rails,yawboakye/rails,ttanimichi/rails,mathieujobin/reduced-rails-for-travis,bogdanvlviv/rails,repinel/rails,jeremy/rails,EmmaB/rails-1,shioyama/rails,pvalena/rails,maicher/rails,illacceptanything/illacceptanything,aditya-kapoor/rails,amoody2108/TechForJustice,fabianoleittes/rails,mathieujobin/reduced-rails-for-travis,rails/rails,marklocklear/rails,ttanimichi/rails,EmmaB/rails-1,illacceptanything/illacceptanything,Spin42/rails,richseviora/rails,prathamesh-sonpatki/rails,Erol/rails,amoody2108/TechForJustice,betesh/rails,MichaelSp/rails,gavingmiller/rails,bradleypriest/rails,yasslab/railsguides.jp,Sen-Zhang/rails,kaspth/rails,coreyward/rails,sergey-alekseev/rails,eileencodes/rails,Spin42/rails,gauravtiwari/rails,maicher/rails,tgxworld/rails,fabianoleittes/rails,rails/rails,mechanicles/rails,vipulnsward/rails,samphilipd/rails,yhirano55/rails,mtsmfm/rails,voray/rails,kddeisz/rails,yhirano55/rails,Spin42/rails,bolek/rails,kirs/rails-1,marklocklear/rails,Sen-Zhang/rails,fabianoleittes/rails,rossta/rails,untidy-hair/rails,elfassy/rails,Envek/rails,eileencodes/rails,repinel/rails,coreyward/rails,schuetzm/rails,yalab/rails,ttanimichi/rails,assain/rails,bradleypriest/rails,kamipo/rails,gfvcastro/rails,flanger001/rails,alecspopa/rails,utilum/rails,mohitnatoo/rails,shioyama/rails,pvalena/rails,kddeisz/rails,Stellenticket/rails,rafaelfranca/omg-rails,Edouard-chin/rails,Vasfed/rails,sergey-alekseev/rails,xlymian/rails,utilum/rails,arjes/rails,georgeclaghorn/rails,lucasmazza/rails,coreyward/rails,kenta-s/rails,illacceptanything/illacceptanything,samphilipd/rails,yahonda/rails,yalab/rails,illacceptanything/illacceptanything,betesh/rails,printercu/rails,georgeclaghorn/rails,MSP-Greg/rails,Erol/rails,tgxworld/rails,MSP-Greg/rails,joonyou/rails,yawboakye/rails,88rabbit/newRails,tjschuck/rails,notapatch/rails,aditya-kapoor/rails,riseshia/railsguides.kr,gfvcastro/rails,MSP-Greg/rails,tijwelch/rails,88rabbit/newRails,untidy-hair/rails,stefanmb/rails,Erol/rails,tjschuck/rails,palkan/rails,arjes/rails,yasslab/railsguides.jp,illacceptanything/illacceptanything,vipulnsward/rails,tijwelch/rails,kenta-s/rails,illacceptanything/illacceptanything,sealocal/rails,kmcphillips/rails,mtsmfm/rails,alecspopa/rails,flanger001/rails,arunagw/rails,hanystudy/rails,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