golang: download 1.4 tarball from github

This will make integration with `shared` option of slapos.recipe.cmmi
easier.

component/golang/buildout.cfg

@@ -21,14 +21,10 @@ environment =
   GOROOT_FINAL=${:location}
   ${:environment-extra}
 
-[golang14-repository]
-<= git-repository
-repository = https://github.com/golang/go.git
-revision = go1.4.3-16-g4d5426a
-
 [golang14]
 <= golang-common
-path = ${golang14-repository:location}
+url = https://github.com/golang/go/archive/go1.4.3-16-g4d5426a.zip
+md5sum = 8ad0d3104cb2cdd59953a5532796e5e8
 environment-extra =
 make-targets= cd src && ./make.bash && cp -alf .. ${:location}