TMF: Synchronize traces on their host ID instead of trace name

TMF: Synchronize traces on their host ID instead of trace name

This allow to synchronize traces with identical names, and will have the
side-effect that different traces from the same host will be automatically
synchronized with the same formula.

Change-Id: Ifbf8da91d581e1cee3c699bd976b1437e661830b
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>
Reviewed-on: https://git.eclipse.org/r/24983
Tested-by: Hudson CI
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>