Fixed typo

[mpscholten]

Fixes a typo in the pListLine parser. IMAP uses Noinferiors instead of Noinferior. That causes lines in the output of IMAP.list that contain Noinferiors to not show up.

E.g. an output like this:

* LIST (\\Noinferiors \\Sent) \"/\" \"Sent\"\r\n

Cannot be parsed with the current parser.