for readability.

Previously, `nochg` responses were treated as failures and the logged
message for all responses was incorrect (either `undef` or "Unknown
reply from Infomaniak").

Background: Hash values are always scalars, so lists of values can
only be stored in hashes in arrayref form.

The following is legal but does not do what one might expect:

    my %h = (
        a => (1, 2),
        b => (3, 4),
    );

The `=>` operator is just a variant of the comma operator, and lists
in list context are flattened, so the above is equivalent to:

    my %h = ('a', 1, 2, 'b', 3, 4);

which is equivalent to:

    my %h = (
        a => 1,
        2 => 'b',
        3 => 4,
    );

which is obviously not what was intended.