e7fabf9e57
We usually mutate some exceptions to OfflineImapError() and it is a whole lot better if such exception will show up with the original traceback, so all valid occurrences of such mutations were transformed to the 3-tuple form of "raise". Had also added coding guidelines document where this re-raise strategy is documented. Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>