OSV-2018-89 Heap-use-after-free in TunnelIPv6Interface::remove_address

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10864 Crash type: Heap-use-after-free READ 4 Crash state: TunnelIPv6Interface::removeaddress nl::wpantund::NCPInstanceBase::unicastaddresswasremoved nl::wpantund::NCPInstanceBase::onmeshprefixwasremoved...