ewsclient: Differentiate between short-circuited and cancelled messages
ewsclient: Differentiate between short-circuited and cancelled messages

Since more than one message is queued, we cancel the rest if any one
of them is successful. This short-circuiting is different from cases
where all messages are cancelled because of a soup_session_abort
triggered by a GCancellable.

Fixes: https://bugzilla.gnome.org/689642

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