[FIX] Do not fail when a None value is given instead of a float when importing special lines of sales orders.
[FIX] Do not fail when a None value is given instead of a float when importing special lines of sales orders.

akretion/connector-magento,ipmobiletech/connector-magento,vitasoa/OpenERP-7.0-Magento,emiprotechnologies/connector-magento,hifly/connector-magento,gurneyalex/connector-magento,MadsackMediaStore/connector-magento,acsone/connector-magento,brain-tec/connector-magento,zhaohuaw/connector-magento,fevxie/connector-magento,Trust-Code/connector-magento,brain-tec/connector-magento,damdam-s/connector-magento,damdam-s/connector-magento,gurneyalex/connector-magento,fevxie/connector-magento,Endika/connector-magento,hifly/connector-magento,vitasoa/OpenERP-7.0-Magento,acsone/connector-magento,ipmobiletech/connector-magento,akretion/connector-magento,Endika/connector-magento,Trust-Code/connector-magento,Antiun/connector-magento,MadsackMediaStore/connector-magento,gurneyalex/connector-magento,Antiun/connector-magento