[release-branch.go1.5] go1.5
[release-branch.go1.5] go1.5

This updates the VERSION file.
The release proper has not happened yet.

Change-Id: I3e33b5f95aede0da8ca1aef0d9c381942873c9a8
Reviewed-on: https://go-review.googlesource.com/13702
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

shines77/go,shines77/go,Stan-Lin-/go,albertjin/golang-go,Stan-Lin-/go,shines77/go,willjunspecial/go,Stan-Lin-/go,nakedgc/go,willjunspecial/go,nakedgc/go,nakedgc/go,albertjin/golang-go,albertjin/golang-go,Stan-Lin-/go,albertjin/golang-go,albertjin/golang-go,nakedgc/go,willjunspecial/go,nakedgc/go,nakedgc/go,willjunspecial/go,albertjin/golang-go,willjunspecial/go,Stan-Lin-/go,nakedgc/go,shines77/go,shines77/go,nakedgc/go,shines77/go,Stan-Lin-/go,willjunspecial/go,Stan-Lin-/go,albertjin/golang-go,willjunspecial/go,shines77/go,albertjin/golang-go,shines77/go,willjunspecial/go,Stan-Lin-/go