Connection exceptions displayed twice in the log

[pepone]

First we trace exception in

https://github.com/zeroc-ice/ice/blob/827fb617431b61f1fe811139f7b7f33beb45dbf0/cpp/src/Ice/ConnectionFactory.cpp#L1120

And then in

https://github.com/zeroc-ice/ice/blob/827fb617431b61f1fe811139f7b7f33beb45dbf0/cpp/src/Ice/ConnectionFactory.cpp#L922

We can probably just remove handleConnectionException or if we keep it we can remove the exception tracing from there and trace the failed endpoint and the next endpoint if any.

[bentoi]

Removing it implies we loose the information that a connection establishment is the result of a retry on the next endpoint of a proxy's endpoint list. Perhaps it's not so useful? Or we could lower down the trace level of this trace (remove the exception) and possibly add a trace at the beginning of the connection establishment to show the endpoint list?

If we review the network tracing, we might want to also consider integrating the Ice.Trace.Retry tracing to the network tracing. Using Ice.Trace.Retry alone isn't so useful without the network tracing and seeing retries with the network tracing is often useful.