Improve traces behavior on component failure

[JulianVentura]

Jaeger will only show traces if they are created and finished.
Currently, we have two scenarios on which a failure in the tracker implies loss in traces.

1. If the tracker is down when a new trace is going to be created, the call will fail and the trace won't be created. The tracker may get up and receive requests related to that same trace, but will ignore them since it hasn't been created.
2. If the tracker is down when a trace is going to be finished, the call will fail and the trace won't be finished.

On both cases, the trace will be lost and with it valid information that could be saved otherwise.