Avoid local message cache expiry clean up when being offline
Avoid local message cache expiry clean up when being offline

When an account is offline, then its locally stored messages
should not be removed due to expiry, such thing should be
done only in online, otherwise it could make message available
in one second and then re-selecting it a second later it being
unavailable, which is rather confusing and unexpected.

GNOME/evolution-mapi,GNOME/evolution-mapi