Fixed: Quota script must ignore maildir which doesn't exist + small fixes

    [feedquote='i-MSCP Github (stable) (nuxwin)','https://github.com/i-MSCP/imscp/commit/a737f3f55a338199967e981fd8e682c80a557df0']

    Code
    1. Fixed: Quota script must ignore maildir which doesn't exist + small fixes

    [/feedquote]