Don't check for NOLOGIN (LOGINDISABLED) capability when imap.authMethod
is specified.
LOGINDISABLED capability doesn't forbid using AUTHENTICATE, so it should
be allowed, or we can't connect to IMAP servers which only accepts
AUTHENTICATE command.
Signed-off-by: Kazuki Yamaguchi <k@rhe.jp> Signed-off-by: Junio C Hamano <gitster@pobox.com>