chore(Makefile): update to go-dev 0.17.0

Includes the go 1.7 toolchain. See https://tip.golang.org/doc/go1.7

Author: mboersma

Makefile

@@ -1,10 +1,8 @@
 SHORT_NAME := minio
 
-export GO15VENDOREXPERIMENT=1
-
 # dockerized development environment variables
 REPO_PATH := github.com/deis/${SHORT_NAME}
-DEV_ENV_IMAGE := quay.io/deis/go-dev:0.9.1
+DEV_ENV_IMAGE := quay.io/deis/go-dev:0.17.0
 DEV_ENV_WORK_DIR := /go/src/${REPO_PATH}
 DEV_ENV_PREFIX := docker run --rm -v ${CURDIR}:${DEV_ENV_WORK_DIR} -w ${DEV_ENV_WORK_DIR}
 DEV_ENV_CMD := ${DEV_ENV_PREFIX} ${DEV_ENV_IMAGE}