If we loop, exit the account synchronization after 3 failed attempts
If we loop, exit the account synchronization after 3 failed attempts

This should get rid of intermittent network failures, but lets us bail
out on permanent errors.

Signed-off-by: Sebastian Spaeth <98dcb2717ddae152d5b359c6ea97e4fe34a29d4c@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <347709267ddd1958560c4c317ea3fd613f10a719@laposte.net>

frioux/offlineimap,frioux/offlineimap