Suffix may be used before it is assigned a value

Suffix may be used before it is assigned a value

    CID 350722 (#5 of 7): Bad use of null-like value (FORWARD_NULL)
        12. invalid_operation: Invalid operation on null-like value suffix.
    145        r.authority.append(
    146            dns.rrset.from_text(
    147                "icky.ptang.zoop.boing." + suffix,
    148                1,
    149                IN,
    150                NS,
    151                "a.bit.longer.ns.name." + suffix,
    152            )
    153        )

(cherry picked from commit 432064f63c3541b3bb40d5505a420e47efd6d30d)