dropbox: fix repeatedly uploading the same files - fixes #2218
dropbox: fix repeatedly uploading the same files - fixes #2218

In #2134 and dfd0f4c5a458b88857be4a035d910ffc5934f6eb some testing
changes got committed by accident which caused this regression.

This patch reverts it to how it was before.

seuffert/rclone,olihey/rclone,yonjah/rclone,B4dM4n/rclone,B4dM4n/rclone,ncw/rclone,ncw/rclone,yonjah/rclone,B4dM4n/rclone,seuffert/rclone,B4dM4n/rclone,olihey/rclone,yonjah/rclone,olihey/rclone,olihey/rclone,ncw/rclone,seuffert/rclone,seuffert/rclone,ncw/rclone,yonjah/rclone