gnu: Remove go-github-com-docker-machine.

Not in use by any other packages in Guix, fails to build: "This
repository has been archived by the owner on Sep 26, 2021. It is now
read-only."

* gnu/packages/golang.scm (go-github-com-docker-machine): Delete variable.

Change-Id: Ic860ddcba326124e707267d04ffc7ef39579dac5

gnu/packages/golang.scm

@@ -2712,33 +2712,6 @@ translation (NAT), proxies, sockets, and transport layer security (TLS).")
 machine friendly values.")
     (license license:asl2.0)))
 
-(define-public go-github-com-docker-machine
-  (let ((commit "7b7a141da84480342357c51838be142bf183b095")
-        (revision "0"))
-    (package
-      (name "go-github-com-docker-machine")
-      (version (git-version "0.0.0" revision commit))
-      (source
-       (origin
-         (method git-fetch)
-         (uri (git-reference
-               (url "https://github.com/docker/machine")
-               (commit commit)))
-         (file-name (git-file-name name version))
-         (sha256
-          (base32
-           "0bavk0lvs462yh0lnmnxi9psi5qv1x3nvzmd2b0drsahlp1gxi8s"))))
-      (build-system go-build-system)
-      (arguments
-       '(#:import-path "github.com/docker/machine"))
-      (home-page "https://github.com/docker/machine")
-      (synopsis "Machine management for a container-centric world")
-      (description
-       "@dfn{Machine} lets you create Docker hosts on your computer, on
-hosting providers, and inside your data center.  It creates servers, installs
-Docker on them, then configures the Docker client to talk to them.")
-      (license license:asl2.0))))
-
 (define-public go-github-com-matrix-org-gomatrix
   (package
     (name "go-github-com-matrix-org-gomatrix")