(cherry picked from commit 2968b2ce)

The Exchange 2010 servers are more strict with respect of recurring
events, they require also PidLidAppointmentTimeZoneDefinitionRecur
property, and claim an error (MESSAGE_CORRUPT) when saving recurring
blobs with missing Reserve2 parts.

It only printed a runtime warning on a console

If there is a message/rfc822 attachment, which is not properly
saved as an embedded message object on the server (which some
older evolution-mapi could do), then these might not be encoded
in base64, rather keep them inline un-encoded.

camel_store_summary_index() is only called when looping over summary
items from 0 to camel_store_summary_count().  But this pattern is not
thread-safe, because another thread could add or remove summary items
while the loop is in progress.

Use camel_store_summary_array() instead to avoid these issues.