It seems the new version of remmina added support for gnome-keyring. I'm not interested in using it, however.
To do that, one can remove remmina-plugins-gnome.so. The application then falls back to its own method of saving the passwords.
Maybe removing/not building that plugin in the first place could be turned into an useflag? That would be great!
(also, we are missing a desktop file ;) )
This has been merged upstream and is available in remmina-9999. I'll keep this open until we have a release.
Fixed in remmina-1.0.0-r1.