golang: v↑ (1.5.3)

This is a security-bugfix release:

From https://golang.org/doc/devel/release.html#go1.5.minor:

    go1.5.3 (released 2016/01/13) includes a security fix to the math/big
    package affecting the crypto/tls package. See the Go 1.5.3 milestone on
    our issue tracker[1] and the release announcement[2] for details.

    [1] https://github.com/golang/go/issues?q=milestone%3AGo1.5.3
    [2] https://golang.org/s/go153announce

I've rebuild helloworld software release and briefly tested helloweb.go
with go 1.5.3 ok.

/reviewed-by: TrustMe
/cc @kazuhiko, !39

component/golang/buildout.cfg

@@ -26,8 +26,8 @@ environment-extra =
 
 [golang15]
 <= golang-common
-url = https://storage.googleapis.com/golang/go1.5.2.src.tar.gz
-md5sum = 38fed22e7b80672291e7cba7fb9c3475
+url = https://storage.googleapis.com/golang/go1.5.3.src.tar.gz
+md5sum = 80a0eac7ab750b01b3f7096a1d4667b8
 
 # go1.5 needs go1.4 to bootstrap
 environment-extra =