Commands run:
```
$ gvt delete github.com/weaveworks/common
$ gvt fetch -revision 59b2b6f8dad04cc1e3538885ddf4ed832095295d github.com/weaveworks/common
```
N.B.: following this commit, build fails with:
```
vendor/github.com/docker/docker/pkg/archive/archive.go:19:2: cannot find package "github.com/docker/docker/pkg/fileutils" in any of:
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/vendor/github.com/docker/docker/pkg/fileutils (vendor tree)
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/pkg/fileutils
	/usr/local/go/src/github.com/docker/docker/pkg/fileutils (from $GOROOT)
	/go/src/github.com/docker/docker/pkg/fileutils (from $GOPATH)
vendor/github.com/fsouza/go-dockerclient/client.go:35:2: cannot find package "github.com/docker/docker/pkg/stdcopy" in any of:
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/pkg/stdcopy (vendor tree)
	/usr/local/go/src/github.com/docker/docker/pkg/stdcopy (from $GOROOT)
	/go/src/github.com/docker/docker/pkg/stdcopy (from $GOPATH)
```
Resolution in subsequent commit.