Migrate to govendor to avoid limitations of godep

- over the course of a project history every maintainer needs to update
  its dependency packages, the problem essentially with godep is manipulating
  GOPATH - this manipulation leads to static objects created at different locations
  which end up conflicting with the overall functionality of golang.

  This also leads to broken builds. There is no easier way out of this other than
  asking developers to do 'godep restore' all the time. Which perhaps as a practice
  doesn't sound like a clean solution. On the other hand 'godep restore' has its own
  set of problems.

- govendor is a right tool but a stop gap tool until we wait for golangs official
  1.5 version which fixes this vendoring issue once and for all.

- govendor provides consistency in terms of how import paths should be handled unlike
  manipulation GOPATH.

  This has advantages
    - no more compiled objects being referenced in GOPATH and build time GOPATH
      manging which leads to conflicts.
    - proper import paths referencing the exact package a project is dependent on.

 govendor is simple and provides the minimal necessary tooling to achieve this.

 For now this is the right solution.

Makefile

@@ -6,10 +6,9 @@ checkdeps:
 
 checkgopath:
 	@echo "Checking if project is at ${GOPATH}"
-	@for mcpath in $(echo ${GOPATH} | sed 's/:/\n/g' | grep -v Godeps); do if [ ! -d ${mcpath}/src/github.com/minio/minio ]; then echo "Project not found in ${mcpath}, please follow instructions provided at https://github.com/minio/minio/blob/master/CONTRIBUTING.md#setup-your-minio-github-repository" && exit 1; fi done
+	@for mcpath in $(echo ${GOPATH} | sed 's/:/\n/g'); do if [ ! -d ${mcpath}/src/github.com/minio/minio ]; then echo "Project not found in ${mcpath}, please follow instructions provided at https://github.com/minio/minio/blob/master/CONTRIBUTING.md#setup-your-minio-github-repository" && exit 1; fi done
 
 getdeps: checkdeps checkgopath
-	@go get github.com/tools/godep && echo "Installed godep:"
 	@go get github.com/golang/lint/golint && echo "Installed golint:"
 	@go get golang.org/x/tools/cmd/vet && echo "Installed vet:"
 	@go get github.com/fzipp/gocyclo && echo "Installed gocyclo:"
@@ -18,53 +17,42 @@ verifiers: getdeps vet fmt lint cyclo
 
 vet:
 	@echo "Running $@:"
-	@go vet ./...
+	@go vet .
+	@go vet github.com/minio/minio/pkg...
 fmt:
 	@echo "Running $@:"
-	@test -z "$$(gofmt -s -l . | grep -v Godeps/_workspace/src/ | tee /dev/stderr)" || \
-		echo "+ please format Go code with 'gofmt -s'"
+	@gofmt -s -l *.go
+	@gofmt -s -l pkg
+
 lint:
 	@echo "Running $@:"
-	@test -z "$$(golint ./... | grep -v Godeps/_workspace/src/ | tee /dev/stderr)"
+	@golint .
+	@golint pkg
 
 cyclo:
 	@echo "Running $@:"
-	@test -z "$$(gocyclo -over 25 . | grep -v Godeps/_workspace/src/ | tee /dev/stderr)"
+	@gocyclo -over 25 .
 
 build: getdeps verifiers
 	@echo "Installing minio:"
-	@godep go generate ./...
-	@godep go test -race ./...
+	@go generate ./...
+	@go test -race github.com/minio/minio/pkg...
 
 gomake-all: build
-	@godep go install github.com/minio/minio
+	@go install github.com/minio/minio
 
 release: genversion
 	@echo "Installing minio for new version.go:"
-	@godep go install github.com/minio/minio
+	@go install github.com/minio/minio
 
 genversion:
 	@echo "Generating new minio version.go"
-	@godep go run genversion.go
-
-godepupdate:
-	@(env bash $(PWD)/buildscripts/updatedeps.sh)
+	@go run genversion.go
 
 install: gomake-all
 
-save:
-	@godep save ./...
-
-restore:
-	@godep restore
-
-env:
-	@godep go env
-
 clean:
 	@echo "Cleaning up all the generated files:"
 	@rm -fv cover.out
 	@rm -fv pkg/utils/split/TESTPREFIX.*
 	@rm -fv minio
-	@godep go clean
-	@find Godeps -name "*.a" -type f -exec rm -vf {} \+