tmf.xml: Delete existing supplementary files when importing xml analysis

tmf.xml: Delete existing supplementary files when importing xml analysis

Previously, if we import a file that was previously loaded once, traces
won't be notified that the file changed.
Now, if the file already exist, the supplementary files for the analysis
are deleted and the related traces are closed.

Change-Id: I62ce6e6f4295db5f0c82e4c77ae73b4e5a4c1b85
Signed-off-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/73648
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Reviewed-by: Hudson CI
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>