Properly set the current folder on file open
Properly set the current folder on file open

This makes sure the next time the file dialog is opened the last folder
used is openend.

CURA-246 #Start-Review

senttech/Cura,totalretribution/Cura,bq/Ultimaker-Cura,fieldOfView/Cura,ynotstartups/Wanhao,ynotstartups/Wanhao,totalretribution/Cura,senttech/Cura,bq/Ultimaker-Cura,hmflash/Cura,markwal/Cura,fieldOfView/Cura,markwal/Cura,ad1217/Cura,Curahelper/Cura,ad1217/Cura,hmflash/Cura,Curahelper/Cura