sync: Fix incorrect "nothing to transfer" message using --delete-before
sync: Fix incorrect "nothing to transfer" message using --delete-before

Before this change the first pass of --delete-before would output
"There was nothing to transfer" and then proceed to transfer things.

This makes sure the message isn't printed in the delete phase.

See: https://forum.rclone.org/t/incorrect-debug-output/15267

ncw/rclone,ncw/rclone,ncw/rclone,ncw/rclone