[golang14] fix TestParseInLocation test: Install package from latest changes...

[golang14] fix TestParseInLocation test: Install package from latest changes on upstream go14 branch

https://github.com/golang/go/commit/4d5426a570c2820c5894a61b52e3dc147e4e7925

golang14 is still failing to build on some server, the commit above fix the
problem on test TestParseInLocation. This is why we install golang14 from upstream go14 branch.

[ kirr: see also relateddiscussion on !133 ]

/reviewed-by @kirr
/reviewed-on !245

component/golang/buildout.cfg

@@ -20,11 +20,14 @@ 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
-url = https://storage.googleapis.com/golang/go1.4-bootstrap-20170531.tar.gz
-md5sum = d2cc61cb9f829b3510ee39c0c5568014
+path = ${golang14-repository:location}
 environment-extra =