docker: Move package dependency from python 2 to 3 for Debian
docker: Move package dependency from python 2 to 3 for Debian

Unfortunately there is no python3 package in rhel-7/centos-7, nor does
this release support alternative RPM dependencies, so keep
"python" in cockpit.spec for the time being.

Fixes #5719
Closes #5784
Reviewed-by: Dominik Perpeet <f7830b2723a5db4fc185058b06cfab4b89a38da9@redhat.com>

Scribery/cockpit,moraleslazaro/cockpit,garrett/cockpit,deryni/cockpit,petervo/cockpit,xhad/cockpit,martinpitt/cockpit,michalskrivanek/cockpit,deryni/cockpit,cockpituous/cockpit,cockpit-project/cockpit,mareklibra/cockpit,xhad/cockpit,Scribery/cockpit,deryni/cockpit,larskarlitski/cockpit,deryni/cockpit,larskarlitski/cockpit,SotolitoLabs/cockpit,petervo/cockpit,cockpituous/cockpit,larsu/cockpit,arilivigni/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,SotolitoLabs/cockpit,dperpeet/cockpit,mareklibra/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,mareklibra/cockpit,sgallagher/cockpit,andreasn/cockpit,sgallagher/cockpit,xhad/cockpit,mareklibra/cockpit,larskarlitski/cockpit,andreasn/cockpit,sgallagher/cockpit,SotolitoLabs/cockpit,michalskrivanek/cockpit,larsu/cockpit,garrett/cockpit,xhad/cockpit,martinpitt/cockpit,Scribery/cockpit,arilivigni/cockpit,mvollmer/cockpit,dperpeet/cockpit,stefwalter/cockpit,petervo/cockpit,petervo/cockpit,harishanand95/cockpit,mareklibra/cockpit,moraleslazaro/cockpit,arilivigni/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,stefwalter/cockpit,arilivigni/cockpit,xhad/cockpit,sgallagher/cockpit,arilivigni/cockpit,martinpitt/cockpit,Scribery/cockpit,michalskrivanek/cockpit,moraleslazaro/cockpit,larsu/cockpit,martinpitt/cockpit,martinpitt/cockpit,arilivigni/cockpit,garrett/cockpit,michalskrivanek/cockpit,stefwalter/cockpit,Scribery/cockpit,dperpeet/cockpit,harishanand95/cockpit,harishanand95/cockpit,moraleslazaro/cockpit,garrett/cockpit,Scribery/cockpit,garrett/cockpit,mvollmer/cockpit,michalskrivanek/cockpit,andreasn/cockpit,mareklibra/cockpit,sgallagher/cockpit,harishanand95/cockpit,michalskrivanek/cockpit,stefwalter/cockpit,sgallagher/cockpit,dperpeet/cockpit,mvollmer/cockpit,larskarlitski/cockpit,Scribery/cockpit,larsu/cockpit,mvollmer/cockpit,mvollmer/cockpit,larsu/cockpit,SotolitoLabs/cockpit,harishanand95/cockpit,dperpeet/cockpit,xhad/cockpit,petervo/cockpit,larskarlitski/cockpit,larskarlitski/cockpit,harishanand95/cockpit,larskarlitski/cockpit,cockpituous/cockpit,petervo/cockpit,stefwalter/cockpit,cockpituous/cockpit,dperpeet/cockpit,cockpituous/cockpit,larsu/cockpit,mareklibra/cockpit,harishanand95/cockpit,xhad/cockpit,andreasn/cockpit,andreasn/cockpit,andreasn/cockpit,petervo/cockpit,dperpeet/cockpit,stefwalter/cockpit,deryni/cockpit,michalskrivanek/cockpit,deryni/cockpit,stefwalter/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,deryni/cockpit,arilivigni/cockpit,sgallagher/cockpit,andreasn/cockpit,cockpituous/cockpit