conn: Remove assert on new listener connection when retrying

Opening a new listener connection can fail in many ways like a bind() permission denied on a low port for instance.

And thus, we should expect to handle an error when creating a new one instead of assert() on it.

To hit the removed assert:

ORPort 80 KeepBindCapabilities 0

Start tor. Then edit torrc:

ORPort :80

HUP tor and the assert is hit.

Fixes #40073 (closed)

Signed-off-by: David Goulet dgoulet@torproject.org