b2: allow manual configuration of backblaze downloadUrl - fixes #2808
b2: allow manual configuration of backblaze downloadUrl - fixes #2808

B4dM4n/rclone,ncw/rclone,ncw/rclone,olihey/rclone,ncw/rclone,B4dM4n/rclone,olihey/rclone,B4dM4n/rclone,olihey/rclone,B4dM4n/rclone,ncw/rclone,olihey/rclone