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/gopkg.in/check.v1/.gitignore

@@ -1,4 +0,0 @@
-_*
-*.swp
-*.[568]
-[568].out

vendor/gopkg.in/check.v1/README.md

@@ -1,20 +0,0 @@
-Instructions
-============
-
-Install the package with:
-
-    go get gopkg.in/check.v1
-    
-Import it with:
-
-    import "gopkg.in/check.v1"
-
-and use _check_ as the package name inside the code.
-
-For more details, visit the project page:
-
-* http://labix.org/gocheck
-
-and the API documentation:
-
-* https://gopkg.in/check.v1

vendor/gopkg.in/check.v1/TODO

@@ -1,2 +0,0 @@
-- Assert(slice, Contains, item)
-- Parallel test support