mms: do not update seen field in markAsUnread operation

This prevents to a seen thread to be notified again after mark as unread

Change-Id: Ib97ded493cdddb261666cffb37bf2f82e827d6a3
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
mms: markAsUnread only read items (ignore seen flag)

Do not mark threads that are only seen

Change-Id: Iffef7823663918ee0dcbecc0241cde71e5a25bca
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>