[MRG] fix bug 1189922 that prevents validation of 0% export tax invoices
[MRG] fix bug 1189922 that prevents validation of 0% export tax invoices

luc-demeyer/account-financial-tools,andhit-r/account-financial-tools,yelizariev/account-financial-tools,Nowheresly/account-financial-tools,alhashash/account-financial-tools,ClearCorp-dev/account-financial-tools,Endika/account-financial-tools,Nowheresly/account-financial-tools,factorlibre/account-financial-tools,Antiun/account-financial-tools,credativUK/account-financial-tools,taktik/account-financial-tools,charbeljc/account-financial-tools,adhoc-dev/oca-account-financial-tools,open-synergy/account-financial-tools,vauxoo-dev/account-financial-tools,Domatix/account-financial-tools,pedrobaeza/account-financial-tools,acsone/account-financial-tools,alhashash/account-financial-tools,VitalPet/account-financial-tools,raycarnes/account-financial-tools,DarkoNikolovski/account-financial-tools,nagyv/account-financial-tools,iDTLabssl/account-financial-tools,syci/account-financial-tools,akretion/account-financial-tools,charbeljc/account-financial-tools,gurneyalex/account-financial-tools,dvitme/account-financial-tools,bringsvor/account-financial-tools,factorlibre/account-financial-tools,acsone/account-financial-tools,andrius-preimantas/account-financial-tools,abstract-open-solutions/account-financial-tools,damdam-s/account-financial-tools,Endika/account-financial-tools,luc-demeyer/account-financial-tools,andrius-preimantas/account-financial-tools,yvaucher/account-financial-tools,xpansa/account-financial-tools,diagramsoftware/account-financial-tools,Domatix/account-financial-tools,rschnapka/account-financial-tools,abstract-open-solutions/account-financial-tools,dvitme/account-financial-tools,open-synergy/account-financial-tools,OpenPymeMx/account-financial-tools,lepistone/account-financial-tools,lepistone/account-financial-tools,cysnake4713/account-financial-tools,damdam-s/account-financial-tools,vauxoo-dev/account-financial-tools,akretion/account-financial-tools,Pexego/account-financial-tools,amoya-dx/account-financial-tools,gurneyalex/account-financial-tools,syci/account-financial-tools,yelizariev/account-financial-tools,bringsvor/account-financial-tools,raycarnes/account-financial-tools,nagyv/account-financial-tools,credativUK/account-financial-tools,Pexego/account-financial-tools,yvaucher/account-financial-tools,open-synergy/account-financial-tools,xpansa/account-financial-tools,Domatix/account-financial-tools,OpenPymeMx/account-financial-tools,VitalPet/account-financial-tools,taktik/account-financial-tools,adhoc-dev/oca-account-financial-tools,acsone/account-financial-tools,pedrobaeza/account-financial-tools,ClearCorp-dev/account-financial-tools,andhit-r/account-financial-tools,Antiun/account-financial-tools,cysnake4713/account-financial-tools,amoya-dx/account-financial-tools,diagramsoftware/account-financial-tools,iDTLabssl/account-financial-tools,rschnapka/account-financial-tools,VitalPet/account-financial-tools,OpenPymeMx/account-financial-tools,DarkoNikolovski/account-financial-tools