kerberos: fix leak in reset_alarms
kerberos: fix leak in reset_alarms

A GDateTime "now" object wasn't getting cleaned up after use.

https://bugzilla.gnome.org/show_bug.cgi?id=726353

halfline/gnome-online-accounts,Distrotech/gnome-online-accounts,ritzk/gnome-online-accounts,dnohales/gnome-online-accounts,halfline/gnome-online-accounts,Distrotech/gnome-online-accounts,halfline/gnome-online-accounts,felipeborges/gnome-online-accounts,ritzk/gnome-online-accounts,felipeborges/gnome-online-accounts,ritzk/gnome-online-accounts,Distrotech/gnome-online-accounts,dnohales/gnome-online-accounts,felipeborges/gnome-online-accounts,dnohales/gnome-online-accounts