manifests: Exclude python again

We cleared up the dependency chain for the nfs-utils-coreos package in
F43 so we can exclude Python again.

See: coreos/fedora-coreos-tracker#1942
Reverts: e70fd15 manifests/fedora-coreos: allow python in F43+ for now

Author: travier

manifests/fedora-coreos.yaml

@@ -221,6 +221,9 @@ postprocess:
     excludes=(
       perl
       perl-interpreter
+      python
+      python3
+      python3-libs
       nodejs
       grubby
       cowsay  # Just in case