works now after several commands
download rpmfusion client-side certificate from
https://admin.rpmfusion.org/accounts/user/gencert
$ cp dogencert /home/martin/.rpmfusion.cert )
$ ssh-add ~/.ssh/id_rsa
$ ssh-add
$ rpmfusion-packager-setup
Setting up RPM Fusion packager environment
Enter your RPM Fusion username: martinkg
~/.rpmfusion-upload-ca.cert already exists - skipping
~/.rpmfusion-server-ca.cert already exists - skipping
Done