fix(select2): hide dropdown if there are no items to show (same as #1588 for bootstrap)
fix(select2): hide dropdown if there are no items to show (same as #1588 for bootstrap)

ivanvoznyakovsky/ui-select,Servoy/ui-select,billypon/ui-select,Jobularity/ui-select,piebe/ui-select,Jefiozie/ui-select,ivanvoznyakovsky/ui-select,granteagon/ui-select-temp,MartinDeHaan/ui-select-submitform,Servoy/ui-select,iOffice/ui-select,Servoy/ui-select,WorktileTech/ui-select,Jobularity/ui-select,Jefiozie/ui-select,Jobularity/ui-select,piebe/ui-select,vettery/ui-select-mirror,ConfidentCannabis/ui-select,WorktileTech/ui-select,angular-ui/ui-select,Vreasy/ui-select,Jefiozie/ui-select,Vreasy/ui-select,prakashn27/ui-select,ConfidentCannabis/ui-select,angular-ui/ui-select,Vreasy/ui-select,piebe/ui-select,ivanvoznyakovsky/ui-select,WorktileTech/ui-select,billypon/ui-select,Crunch-io/ui-select,looker/ui-select,oncompass/ui-select,looker/ui-select,oncompass/ui-select,iOffice/ui-select,billypon/ui-select,Crunch-io/ui-select,ConfidentCannabis/ui-select,prakashn27/ui-select,oncompass/ui-select,granteagon/ui-select-temp,Crunch-io/ui-select,prakashn27/ui-select,MartinDeHaan/ui-select-submitform,angular-ui/ui-select,MartinDeHaan/ui-select-submitform,granteagon/ui-select-temp,vettery/ui-select-mirror,looker/ui-select