Remove defunkt allow_backord_shipping config
Remove defunkt allow_backord_shipping config

https://github.com/spree/spree/commit/bce76f40c40d3ae20e97cdb745fd5ce967b9176e

Fixes #6380

sunny2601/spree,pulkit21/spree,CJMrozek/spree,grzlus/spree,raow/spree,TimurTarasenko/spree,reidblomquist/spree,piousbox/spree,siddharth28/spree,jaspreet21anand/spree,kewaunited/spree,hifly/spree,rajeevriitm/spree,rajeevriitm/spree,vinsol/spree,softr8/spree,APohio/spree,radarseesradar/spree,jaspreet21anand/spree,omarsar/spree,progsri/spree,gautamsawhney/spree,gregoryrikson/spree-sample,groundctrl/spree,quentinuys/spree,vmatekole/spree,APohio/spree,rajeevriitm/spree,robodisco/spree,zaeznet/spree,jeffboulet/spree,fahidnasir/spree,Lostmyname/spree,moneyspyder/spree,cutefrank/spree,mleglise/spree,siddharth28/spree,vinayvinsol/spree,DarkoP/spree,shaywood2/spree,wolfieorama/spree,shekibobo/spree,rajeevriitm/spree,ayb/spree,pervino/spree,builtbybuffalo/spree,imella/spree,piousbox/spree,jimblesm/spree,jaspreet21anand/spree,moneyspyder/spree,moneyspyder/spree,locomotivapro/spree,hifly/spree,ayb/spree,maybii/spree,hifly/spree,useiichi/spree,vinsol/spree,ayb/spree,pervino/spree,locomotivapro/spree,jasonfb/spree,ahmetabdi/spree,pervino/spree,SadTreeFriends/spree,fahidnasir/spree,AgilTec/spree,calvinl/spree,edgward/spree,imella/spree,Lostmyname/spree,zamiang/spree,alvinjean/spree,volpejoaquin/spree,sfcgeorge/spree,yushine/spree,Kagetsuki/spree,CJMrozek/spree,pulkit21/spree,njerrywerry/spree,brchristian/spree,zaeznet/spree,ramkumar-kr/spree,shekibobo/spree,quentinuys/spree,sunny2601/spree,progsri/spree,tesserakt/clean_spree,zaeznet/spree,caiqinghua/spree,piousbox/spree,orenf/spree,builtbybuffalo/spree,maybii/spree,beni55/spree,cutefrank/spree,jparr/spree,builtbybuffalo/spree,yushine/spree,rakibulislam/spree,karlitxo/spree,gregoryrikson/spree-sample,jparr/spree,TrialGuides/spree,karlitxo/spree,berkes/spree,DarkoP/spree,yiqing95/spree,vinsol/spree,Lostmyname/spree,NerdsvilleCEO/spree,Hawaiideveloper/shoppingcart,lsirivong/spree,brchristian/spree,NerdsvilleCEO/spree,groundctrl/spree,lyzxsc/spree,jeffboulet/spree,azranel/spree,CJMrozek/spree,volpejoaquin/spree,Engeltj/spree,jparr/spree,pulkit21/spree,cutefrank/spree,radarseesradar/spree,shaywood2/spree,Engeltj/spree,mleglise/spree,fahidnasir/spree,pervino/spree,rakibulislam/spree,lsirivong/spree,jasonfb/spree,berkes/spree,AgilTec/spree,Engeltj/spree,mleglise/spree,edgward/spree,caiqinghua/spree,SadTreeFriends/spree,edgward/spree,reidblomquist/spree,abhishekjain16/spree,JuandGirald/spree,adaddeo/spree,tesserakt/clean_spree,welitonfreitas/spree,reidblomquist/spree,useiichi/spree,ramkumar-kr/spree,thogg4/spree,progsri/spree,tomash/spree,welitonfreitas/spree,zaeznet/spree,mindvolt/spree,FadliKun/spree,adaddeo/spree,ahmetabdi/spree,NerdsvilleCEO/spree,SadTreeFriends/spree,grzlus/spree,kewaunited/spree,sfcgeorge/spree,priyank-gupta/spree,grzlus/spree,nooysters/spree,Hawaiideveloper/shoppingcart,shaywood2/spree,TimurTarasenko/spree,yushine/spree,CJMrozek/spree,vinayvinsol/spree,AgilTec/spree,vcavallo/spree,jeffboulet/spree,madetech/spree,vmatekole/spree,sfcgeorge/spree,brchristian/spree,JDutil/spree,vinayvinsol/spree,tesserakt/clean_spree,KMikhaylovCTG/spree,miyazawatomoka/spree,raow/spree,mindvolt/spree,madetech/spree,njerrywerry/spree,lsirivong/spree,robodisco/spree,njerrywerry/spree,jimblesm/spree,jaspreet21anand/spree,radarseesradar/spree,dafontaine/spree,madetech/spree,sliaquat/spree,odk211/spree,mleglise/spree,lsirivong/spree,thogg4/spree,softr8/spree,tancnle/spree,omarsar/spree,omarsar/spree,calvinl/spree,jasonfb/spree,volpejoaquin/spree,NerdsvilleCEO/spree,mindvolt/spree,tomash/spree,patdec/spree,priyank-gupta/spree,orenf/spree,JuandGirald/spree,shekibobo/spree,hoanghiep90/spree,hoanghiep90/spree,volpejoaquin/spree,APohio/spree,maybii/spree,quentinuys/spree,kewaunited/spree,miyazawatomoka/spree,tancnle/spree,vinayvinsol/spree,CiscoCloud/spree,orenf/spree,softr8/spree,wolfieorama/spree,gregoryrikson/spree-sample,DynamoMTL/spree,sliaquat/spree,odk211/spree,dafontaine/spree,priyank-gupta/spree,gautamsawhney/spree,beni55/spree,adaddeo/spree,edgward/spree,groundctrl/spree,yiqing95/spree,locomotivapro/spree,alejandromangione/spree,karlitxo/spree,ramkumar-kr/spree,ahmetabdi/spree,reidblomquist/spree,alejandromangione/spree,pulkit21/spree,fahidnasir/spree,calvinl/spree,JuandGirald/spree,SadTreeFriends/spree,jeffboulet/spree,sliaquat/spree,thogg4/spree,nooysters/spree,alejandromangione/spree,patdec/spree,DarkoP/spree,robodisco/spree,softr8/spree,trigrass2/spree,jimblesm/spree,moneyspyder/spree,JDutil/spree,lyzxsc/spree,APohio/spree,DynamoMTL/spree,TimurTarasenko/spree,CiscoCloud/spree,azranel/spree,priyank-gupta/spree,zamiang/spree,locomotivapro/spree,JDutil/spree,thogg4/spree,Lostmyname/spree,nooysters/spree,tomash/spree,hoanghiep90/spree,joanblake/spree,hifly/spree,JuandGirald/spree,berkes/spree,rakibulislam/spree,brchristian/spree,mindvolt/spree,sunny2601/spree,JDutil/spree,shaywood2/spree,DynamoMTL/spree,shekibobo/spree,radarseesradar/spree,useiichi/spree,KMikhaylovCTG/spree,abhishekjain16/spree,berkes/spree,TrialGuides/spree,tancnle/spree,trigrass2/spree,AgilTec/spree,firman/spree,tancnle/spree,joanblake/spree,firman/spree,TimurTarasenko/spree,grzlus/spree,nooysters/spree,firman/spree,tomash/spree,karlitxo/spree,dafontaine/spree,njerrywerry/spree,yiqing95/spree,abhishekjain16/spree,vcavallo/spree,sfcgeorge/spree,caiqinghua/spree,TrialGuides/spree,FadliKun/spree,abhishekjain16/spree,orenf/spree,welitonfreitas/spree,piousbox/spree,trigrass2/spree,KMikhaylovCTG/spree,raow/spree,trigrass2/spree,quentinuys/spree,alvinjean/spree,gautamsawhney/spree,wolfieorama/spree,zamiang/spree,progsri/spree,lyzxsc/spree,odk211/spree,wolfieorama/spree,adaddeo/spree,Engeltj/spree,FadliKun/spree,tesserakt/clean_spree,lyzxsc/spree,KMikhaylovCTG/spree,jparr/spree,raow/spree,alvinjean/spree,robodisco/spree,beni55/spree,patdec/spree,vmatekole/spree,alejandromangione/spree,sliaquat/spree,rakibulislam/spree,Kagetsuki/spree,azranel/spree,dafontaine/spree,siddharth28/spree,Kagetsuki/spree,ayb/spree,hoanghiep90/spree,omarsar/spree,cutefrank/spree,imella/spree,DynamoMTL/spree,ahmetabdi/spree,zamiang/spree,builtbybuffalo/spree,joanblake/spree,calvinl/spree,yiqing95/spree,DarkoP/spree,kewaunited/spree,Hawaiideveloper/shoppingcart,CiscoCloud/spree,FadliKun/spree,yushine/spree,miyazawatomoka/spree,siddharth28/spree,jasonfb/spree,beni55/spree,odk211/spree,alvinjean/spree,madetech/spree,jimblesm/spree,TrialGuides/spree,sunny2601/spree,patdec/spree,gautamsawhney/spree,caiqinghua/spree,miyazawatomoka/spree,vcavallo/spree,vcavallo/spree,ramkumar-kr/spree,vmatekole/spree,joanblake/spree,vinsol/spree,useiichi/spree,maybii/spree,azranel/spree,Hawaiideveloper/shoppingcart,gregoryrikson/spree-sample,groundctrl/spree,CiscoCloud/spree,firman/spree,welitonfreitas/spree,Kagetsuki/spree