Failed ping_host_add() adds disfunctional pinger

[ghost]

I've tried running simple code using liboping and it fails to run as non-root with "Operation not permitted" returned from ping_host_add() on latest Ubuntu. Which is expected unless we have sufficient permissions via CAP_NET_*.

Despite ping_host_add() returning "Operation not permitted" the host is apparently added to the pingobj_t nevertheless - at least ping_iterator_count() returns incremented number.

Which later on causes following error:
liboping.c:1419: ping_send: Assertion max_fd != -1' failed.`
which results in SIGABRT.

That's with liboping0 v1.10.0-2 installed from the repo.

I do believe that if ping_host_add() returns error than host shouldn't be added to avoid this sort of confusions.