[packaging] review configure_registry script
[packaging] review configure_registry script

So that it prompts the user if he is sure, since this will overwrite
local configuration, plus it is not needed if the registry is not in
this machine.

It will also create a backup copy so that this step can be rolled back.

morodin/Portus,bencevans/Portus,angry-tony/Portus-20170827,vitorarins/Portus,mssola/Portus,armbuilds/portus,armbuilds/portus,bencevans/Portus,morodin/Portus,vpereira/Portus,thuongdinh/Portus,jloehel/Portus,bencevans/Portus,SUSE/Portus,vpereira/Portus,vitorarins/Portus,kwk/Portus,SUSE/Portus,jloehel/Portus,angry-tony/Portus-20170827,krishnak9/Portus,mssola/Portus,SUSE/Portus,jloehel/Portus,kwk/Portus,vpereira/Portus,vitorarins/Portus,krishnak9/Portus,thuongdinh/Portus,krishnak9/Portus,morodin/Portus,krishnak9/Portus,kwk/Portus,mssola/Portus,angry-tony/Portus-20170827,thuongdinh/Portus,SUSE/Portus,armbuilds/portus,mssola/Portus,angry-tony/Portus-20170827