In case we misconfigured a server name or are otherwise offline, a
socket.gaierror will be raised when attempting to connect. We catch that
case and raise an OfflineImapError with severity ERROR.REPO, meaning we
should stop syncing this account and continue with the next one.
Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>