acd: Fix download of large files failing - Fixes #1501
acd: Fix download of large files failing - Fixes #1501

Previously it was necessary to work around large files failing to
download with `--acd-templink-threshold`.  This change makes that flag
obsolete and all files should download.  Templinks may be useful under
some circumstances though the flag isn't being removed.

It does this by filtering `Authorization:` headers out in the
transport if the authorization is supplied in the URL.  This prevents
the "Only one auth mechanism allowed; only the X-Amz-Algorithm query
parameter, Signature query string parameter or the Authorization
header should be specified" error from AWS.

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