upnp: add compatibility for miniupnpc 2.2.8
Summary:
See: https://github.com/miniupnp/miniupnp/commit/c0a50ce33e3b99ce8a96fd43049bb5b53ffac62f The return value of 2 now indicates: "A valid connected IGD has been found but its IP address is reserved (non routable)" We continue to ignore any return value other than 1.
Backport of core#30283.
Test Plan:
On Arch:
ninja
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D16434