I'm not even sure you can do this without the Gnome-Keyring but here goes.
If you have a wired connection you could setup a basic connection like this
Open a terminal
Applications > Accessories > Terminal
I see gksu was removed so have to try sudo or maybe without the sudo part at all
Put this in it, the first part should already be there so just add the second part which is in bold
sudo gedit /etc/network/interfaces
Save and close it.
iface lo inet loopback
iface eth0 inet dhcp
While you wont have a network manager applet to show you it's connected it should connect.
Try going somewhere or running
sudo apt-get update
Once you have network manager and the network manager applet back edit the file again and remove those 2 lines but be sure NOT to remove the first 2 lines.