Require go1.6 for building rclone

This is required because google.golang.org/grpc needs it.

.travis.yml

@@ -4,7 +4,6 @@ osx_image: xcode7.3
 os:
 - linux
 go:
-- 1.5.4
 - 1.6.4
 - 1.7.4
 - 1.8.1

Makefile

@@ -6,8 +6,6 @@ GO_VERSION := $(shell go version)
 GO_FILES := $(shell go list ./... | grep -v /vendor/ )
 GO_LATEST := $(findstring go1.8,$(GO_VERSION))
 BETA_URL := https://beta.rclone.org/$(TAG)/
-# Only needed for Go 1.5
-export GO15VENDOREXPERIMENT=1
 
 .PHONY: rclone
 

docs/content/install.md

@@ -67,7 +67,7 @@ Run `rclone config` to setup. See [rclone config docs](/docs/) for more details.
 
 ## Install from source ##
 
-Make sure you have at least [Go](https://golang.org/) 1.5 installed.
+Make sure you have at least [Go](https://golang.org/) 1.6 installed.
 Make sure your `GOPATH` is set, then:
 
     go get -u -v github.com/ncw/rclone

fs/versioncheck.go

@@ -1,7 +1,7 @@
-//+build !go1.5
+//+build !go1.6
 
 package fs
 
-// Upgrade to Go version 1.5 to compile rclone - latest stable go
+// Upgrade to Go version 1.6 to compile rclone - latest stable go
 // compiler recommended.
-func init() { Go_version_1_5_required_for_compilation() }
+func init() { Go_version_1_6_required_for_compilation() }