dashboard: revert Alpine GO_EXTLINK_ENABLED=1 change

See https://github.com/golang/go/issues/19938#issuecomment-297235206

Made things worse.

Updates golang/go#19938

Change-Id: I6c3e798c0b61ea5ee2c43af0aea5ee56e0f52032
Reviewed-on: https://go-review.googlesource.com/41812
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
1 file changed