Revert "pull the rpms from the Cloud install tree"

This reverts commit 8aa2d66e03.
There is some bug in pungi that causes this not to work for now so let's
revert so we can still get built images until we figure that out.

Signed-off-by: Dusty Mabe <dusty@dustymabe.com>

fedora-atomic.conf

@@ -322,7 +322,7 @@ image_build = {
 ostree_installer = [
     ("^Atomic$", {
         "x86_64": {
-            "source_repo_from": "Cloud",
+            "source_repo_from": "https://kojipkgs.fedoraproject.org/pub/alt/stage/25_RC-1.3/Everything/$arch/os/",
             "release": None,
             "installpkgs": ["fedora-productimg-atomic"],
             "add_template": ["atomic-installer/lorax-configure-repo.tmpl"],