[FIX] stock_product_variants: About singleton error
[FIX] stock_product_variants: About singleton error

agaldona/odoomrp-wip-1,factorlibre/odoomrp-wip,esthermm/odoomrp-wip,Eficent/odoomrp-wip,agaldona/odoomrp-wip-1,sergiocorato/odoomrp-wip,diagramsoftware/odoomrp-wip,Daniel-CA/odoomrp-wip-public,Eficent/odoomrp-wip,oihane/odoomrp-wip,diagramsoftware/odoomrp-wip,odoomrp/odoomrp-wip,jobiols/odoomrp-wip,jobiols/odoomrp-wip,odoomrp/odoomrp-wip,factorlibre/odoomrp-wip,oihane/odoomrp-wip,esthermm/odoomrp-wip,Daniel-CA/odoomrp-wip-public,sergiocorato/odoomrp-wip