folder/IMAP: fix typo with maxsize and maxage.
folder/IMAP: fix typo with maxsize and maxage.

Signed-off-by: Bao Haojun <efa934c44088351d2e6a54e353735c5ff1adc25f@gmail.com>
Signed-off-by: Nicolas Sebrecht <347709267ddd1958560c4c317ea3fd613f10a719@laposte.net>

frioux/offlineimap,frioux/offlineimap