Replace godep with vndr

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)

vendor/github.com/yvasiyarov/newrelic_platform_go/.travis.yml

@@ -1 +0,0 @@
-language: go

vendor/github.com/yvasiyarov/newrelic_platform_go/README.md

@@ -1,11 +0,0 @@
-New Relic Platform Agent SDK for Go(golang)
-====================
-
-[![Build Status](https://travis-ci.org/yvasiyarov/newrelic_platform_go.png?branch=master)](https://travis-ci.org/yvasiyarov/newrelic_platform_go)
-
-This package provide very simple interface to NewRelic Platform http://newrelic.com/platform
-
-For example of usage see examples/wave_plugin.go
-
-For real-word example, you can have a look at:   
-https://github.com/yvasiyarov/newrelic_sphinx   

vendor/github.com/yvasiyarov/newrelic_platform_go/nut.json

@@ -1,15 +0,0 @@
-{
-  "Version": "0.0.1",
-  "Vendor": "yvasiyarov",
-  "Authors": [
-    {
-      "FullName": "Yuriy Vasiyarov",
-      "Email": "varyous@gmail.com"
-    }
-  ],
-  "ExtraFiles": [
-    "README.md",
-    "LICENSE"
-  ],
-  "Homepage": "https://github.com/yvasiyarov/newrelic_platform_go"
-}