Added tiered CA shuffling for CA choices
Added tiered CA shuffling for CA choices

tdfischer/lets-encrypt-preview,ruo91/letsencrypt,luorenjin/letsencrypt,TheBoegl/letsencrypt,sjerdo/letsencrypt,rugk/letsencrypt,g1franc/lets-encrypt-preview,goofwear/letsencrypt,Jadaw1n/letsencrypt,kuba/letsencrypt,jtl999/certbot,stewnorriss/letsencrypt,rutsky/letsencrypt,digideskio/lets-encrypt-preview,piru/letsencrypt,skynet/letsencrypt,PeterMosmans/letsencrypt,martindale/letsencrypt,armersong/letsencrypt,diracdeltas/lets-encrypt-preview,ahojjati/letsencrypt,jsha/letsencrypt,brentdax/letsencrypt,rlustin/letsencrypt,Jonadabe/letsencrypt,rugk/letsencrypt,VladimirTyrin/letsencrypt,thanatos/lets-encrypt-preview,lmcro/letsencrypt,BKreisel/letsencrypt,sapics/letsencrypt,jmaurice/letsencrypt,deserted/letsencrypt,lmcro/letsencrypt,tdfischer/lets-encrypt-preview,diracdeltas/lets-encrypt-preview,lbeltrame/letsencrypt,rutsky/letsencrypt,g1franc/lets-encrypt-preview,mrb/letsencrypt,Jonadabe/letsencrypt,vcavallo/letsencrypt,BKreisel/letsencrypt,ruo91/letsencrypt,ghyde/letsencrypt,hsduk/lets-encrypt-preview,Bachmann1234/letsencrypt,Sveder/letsencrypt,letsencrypt/letsencrypt,goofwear/letsencrypt,twstrike/le_for_patching,brentdax/letsencrypt,bsmr-misc-forks/letsencrypt,piru/letsencrypt,bestwpw/letsencrypt,xgin/letsencrypt,jmhodges/letsencrypt,jtl999/certbot,tyagi-prashant/letsencrypt,DavidGarciaCat/letsencrypt,hlieberman/letsencrypt,hsduk/lets-encrypt-preview,jsha/letsencrypt,fmarier/letsencrypt,luorenjin/letsencrypt,thanatos/lets-encrypt-preview,modulexcite/letsencrypt,Hasimir/letsencrypt,martindale/letsencrypt,Sveder/letsencrypt,solidgoldbomb/letsencrypt,wteiken/letsencrypt,BillKeenan/lets-encrypt-preview,modulexcite/letsencrypt,hlieberman/letsencrypt,xgin/letsencrypt,kevinlondon/letsencrypt,PeterMosmans/letsencrypt,letsencrypt/letsencrypt,ghyde/letsencrypt,VladimirTyrin/letsencrypt,stewnorriss/letsencrypt,wteiken/letsencrypt,stweil/letsencrypt,fmarier/letsencrypt,Hasimir/letsencrypt,BillKeenan/lets-encrypt-preview,deserted/letsencrypt,jmaurice/letsencrypt,sjerdo/letsencrypt,solidgoldbomb/letsencrypt,beermix/letsencrypt,lbeltrame/letsencrypt,stweil/letsencrypt,ahojjati/letsencrypt,TheBoegl/letsencrypt,twstrike/le_for_patching,riseofthetigers/letsencrypt,vcavallo/letsencrypt,armersong/letsencrypt,jmhodges/letsencrypt,Jadaw1n/letsencrypt,mitnk/letsencrypt,kevinlondon/letsencrypt,rlustin/letsencrypt,sapics/letsencrypt,skynet/letsencrypt,bestwpw/letsencrypt,riseofthetigers/letsencrypt,Bachmann1234/letsencrypt,digideskio/lets-encrypt-preview,tyagi-prashant/letsencrypt,mrb/letsencrypt,beermix/letsencrypt,dietsche/letsencrypt,kuba/letsencrypt,bsmr-misc-forks/letsencrypt,DavidGarciaCat/letsencrypt,mitnk/letsencrypt,dietsche/letsencrypt