Upgrade to go 1.5.3

Signed-off-by: David Gageot <david@gageot.net>

CONTRIBUTING.md

@@ -18,7 +18,7 @@ guidelines](https://github.com/docker/docker/blob/master/CONTRIBUTING.md).
 
 The requirements to build Machine are:
 
-1.  A running instance of Docker or a Golang 1.5.2 development environment
+1.  A running instance of Docker or a Golang 1.5.3 development environment
 2.  The `bash` shell
 3.  [Make](https://www.gnu.org/software/make/)
 

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.5.2
+FROM golang:1.5.3
 
 RUN go get  github.com/golang/lint/golint \
             github.com/mattn/goveralls \

Godeps/Godeps.json

@@ -1,6 +1,6 @@
 {
 	"ImportPath": "github.com/docker/machine",
-	"GoVersion": "go1.5.2",
+	"GoVersion": "go1.5",
 	"Packages": [
 		"github.com/docker/machine",
 		"github.com/docker/machine/cmd",

circle.yml

@@ -6,7 +6,7 @@ machine:
     - git clone https://github.com/sstephenson/bats.git && cd bats && sudo ./install.sh /usr/local
 
   post:
-    - gvm install go1.5.2 -B --name=stable
+    - gvm install go1.5.3 -B --name=stable
 
   environment:
   # Convenient shortcuts to "common" locations