Migrate to dep (#3972)

* Update makefile to use dep

* Migrate to dep

* Fix some deps

* Try to find a better version for golang.org/x/net

* Try to find a better version for golang.org/x/oauth2

vendor/gopkg.in/ldap.v2/Makefile

@@ -1,42 +0,0 @@
-.PHONY: default install build test quicktest fmt vet lint 
-
-default: fmt vet lint build quicktest
-
-install:
-	go get -t -v ./...
-
-build:
-	go build -v ./...
-
-test:
-	go test -v -cover ./...
-
-quicktest:
-	go test ./...
-
-# Capture output and force failure when there is non-empty output
-fmt:
-	@echo gofmt -l .
-	@OUTPUT=`gofmt -l . 2>&1`; \
-	if [ "$$OUTPUT" ]; then \
-		echo "gofmt must be run on the following files:"; \
-		echo "$$OUTPUT"; \
-		exit 1; \
-	fi
-
-# Only run on go1.5+
-vet:
-	go tool vet -atomic -bool -copylocks -nilfunc -printf -shadow -rangeloops -unreachable -unsafeptr -unusedresult .
-
-# https://github.com/golang/lint
-# go get github.com/golang/lint/golint
-# Capture output and force failure when there is non-empty output
-# Only run on go1.5+
-lint:
-	@echo golint ./...
-	@OUTPUT=`golint ./... 2>&1`; \
-	if [ "$$OUTPUT" ]; then \
-		echo "golint errors:"; \
-		echo "$$OUTPUT"; \
-		exit 1; \
-	fi

vendor/gopkg.in/ldap.v2/README.md

@@ -1,53 +0,0 @@
-[![GoDoc](https://godoc.org/gopkg.in/ldap.v2?status.svg)](https://godoc.org/gopkg.in/ldap.v2)
-[![Build Status](https://travis-ci.org/go-ldap/ldap.svg)](https://travis-ci.org/go-ldap/ldap)
-
-# Basic LDAP v3 functionality for the GO programming language.
-
-## Install
-
-For the latest version use:
-
-    go get gopkg.in/ldap.v2
-
-Import the latest version with:
-
-    import "gopkg.in/ldap.v2"
-
-## Required Libraries:
-
- - gopkg.in/asn1-ber.v1
-
-## Features:
-
- - Connecting to LDAP server (non-TLS, TLS, STARTTLS)
- - Binding to LDAP server
- - Searching for entries
- - Filter Compile / Decompile
- - Paging Search Results
- - Modify Requests / Responses
- - Add Requests / Responses
- - Delete Requests / Responses
-
-## Examples:
-
- - search
- - modify
-
-## Contributing:
-
-Bug reports and pull requests are welcome!
-
-Before submitting a pull request, please make sure tests and verification scripts pass:
-```
-make all
-```
-
-To set up a pre-push hook to run the tests and verify scripts before pushing:
-```
-ln -s ../../.githooks/pre-push .git/hooks/pre-push
-```
-
----
-The Go gopher was designed by Renee French. (http://reneefrench.blogspot.com/)
-The design is licensed under the Creative Commons 3.0 Attributions license.
-Read this article for more details: http://blog.golang.org/gopher