for IP in $(grep ^ignore /etc/fail2ban/jail.local | awk '{for(i=4;i<=NF;++i)print $i}'); do sudo fail2ban-client set ssh unbanip ${IP}; done

or

# Ignoreip = 127.0.0.1 <<-- Start at the 4th field and remove

for IP in $(grep ^ignore /etc/fail2ban/jail.local |  awk '{for(i=4;i<=NF;++i)print $i}');
do 
  sudo fail2ban-client set ssh unbanip ${IP};
done