This patch fix the beavior of the distributed tracing reporter.
1. For developer build we don't append the date
* We don't need to separate service instances in jaeger (search by trace ID)
* It's usually 0000-00-000 anyway as release.sh is not used for dev builds
2. Tracing ID MUST be unique
* Instead of trusting the user to set a unique value (how can they do it?), we generate a random number
3. To make it possible to find the trace, there is a new flag to print out the generated tracing ID
4. Monkit `remoteTrace` call is replaced with normal monkit Task.
* remoteTrace call assumes that we have a parent span in an other service (which is already sent to the server)
* Here we must send out the parent span, as this is the beginning of the trace
5. We properly close the Jaeger UDP collector, and we wait until remaining messages are sent out
Change-Id: Iabf5abf25f4f20881188f88edcbadca95ac74927
26444194c2