only update the excludeTracks when it is not undefined
only update the excludeTracks when it is not undefined

fmsouza/mangiare,TobiasSchaeuble/HMAD,nReality/SUGSA-ScrumGathering-App2016,nReality/AgileAfricaConf-app,francarmona/ionice-contryside-events-app,ericel/weytindey,pierrecabriere/Greencharge,kumarnavinrai/finalmcu,nReality/SUGSA-ScrumGathering-App2016,nReality/AgileAfricaConf-app,nReality/AgileAfricaConf-app,driftyco/ionic-conference-app,fmsouza/mangiare,ericel/weytindey,TobiasSchaeuble/HMAD,nReality/AgileAfricaConf-app,nReality/AgileAfricaConf-app,francarmona/ionice-contryside-events-app,tommy-boy/AMZNDEALS,fmsouza/mangiare,Beslinda/catalogIonicApp,nReality/SUGSA-ScrumGathering-App2016,kumarnavinrai/finalmcu,abdolmajidazad/neveshtak,subsolo/ITHC,kumarnavinrai/finalmcu,nReality/AgileAfricaConf-app,tommy-boy/AMZNDEALS,subsolo/ITHC,nReality/SUGSA-ScrumGathering-App2016,laodice/ionic-conference-app-session2,nReality/AgileAfricaConf-app,laodice/ionic-conference-app-session2,Beslinda/catalogIonicApp,francarmona/ionice-contryside-events-app,driftyco/ionic-conference-app,sinholic/aero-flyer,pierrecabriere/Greencharge,minhlong/NamHoa-Ionic,laodice/ionic-conference-app-session2,Beslinda/catalogIonicApp,sinholic/aero-flyer,sinholic/aero-flyer,minhlong/NamHoa-Ionic,TobiasSchaeuble/HMAD,ericel/weytindey,nReality/SUGSA-ScrumGathering-App2016,nReality/SUGSA-ScrumGathering-App2016,tommy-boy/AMZNDEALS,abdolmajidazad/neveshtak,fmsouza/mangiare,abdolmajidazad/neveshtak,driftyco/ionic-conference-app,nReality/SUGSA-ScrumGathering-App2016,pierrecabriere/Greencharge,subsolo/ITHC,minhlong/NamHoa-Ionic