Fix bug where cached keys were keeping around dead sessions.
Fix bug where cached keys were keeping around dead sessions.

ekr/nss-old,ekr/nss-old,nmav/nss,nmav/nss,nmav/nss,ekr/nss-old,nmav/nss,nmav/nss,nmav/nss,ekr/nss-old,ekr/nss-old,nmav/nss,ekr/nss-old,ekr/nss-old