Comment 7 for bug 566046

Notes:

 * Create a new user, log in the first time (no autologin) -> creates "login" keyring and "User Keys" password entry

After every action below, log out and back into GNOME:

 * Remove "User Keys" password entry -> no change, "User Keys" is not regenerated
 * Remove entire "Passwords: login" keyring -> "Passwords: login" keyring is recreated, but not "User Keys"
 * rm .gnome2/keyrings/login.keyring -> "Passwords: login" keyring is recreated (and login.keyring file), but not "User Keys"
 * rm .gnome2/keyrings/{login.keyring,user.keystore} ->"Passwords: login" keyring is recreated with "User Keys"
 * Remove "User Keys" password entry and rm .gnome2/keyrings/user.keystore -> "User Keys" password is recreated

Logging into a VT and starting gnome-keyring-daemon by hand does not recreate user.keystore, so it really seems to be pam_gnome_keyring.so.