Failed listening attempt cause other listeners to not get started.

[fovea1959]

Describe the bug
If there is an error in setting up a listening socket, other listening sockets may not get set up.

To Reproduce
Steps to reproduce the behavior:

1. Apply the attached patch and build. This patch adds some debugging code to npu_net.c.
2. Bring up NOS2.8.7 as non-root. Attempts to listen on port 175 will fail, and the output will show that npuNetThread will not try to start other listeners once that has happened.

Expected behavior
I would expect attempts to connect to other ports after the attempt to connect to port 175 fails.

Screenshots
See this discussion item

Additional context
PR is on the way.

[fovea1959]

patch for exposing problem has typo. This patch is correct.

[fovea1959]

PR #166 submitted.