dl: fix paths for go1.12.15 and go1.13.6

Change-Id: I45216ee179984ead751eb1a642ed73a3667cf87e
Reviewed-on: https://go-review.googlesource.com/c/dl/+/214219
Run-TryBot: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2 files changed