Updates resumable hash implementation to Go 1.8 equivalent. This should
be a major speedup, since it includes a number of optimizations from Go
1.7.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Vndr has a simpler configuration and allows pointing to forked
packages. Additionally other docker projects are now using
vndr making vendoring in distribution more consistent.
Updates letsencrypt to use fork.
No longer uses sub-vendored packages.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
