tmf.xml: replace exception with log error message in TmfXmlStateValue

tmf.xml: replace exception with log error message in TmfXmlStateValue

This patch removes an exception that blocks the execution of Trace
Compass when hit. The exception is replaced by a log error message.

Change-Id: I684cbac6038665329a61d16720ec689961209f34
Signed-off-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/79442
Reviewed-by: Hudson CI
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>