Changes

releng: Execute dmg packaging in pre-integration-test phase

This should make sure that it's executed after archive-products is
executed when profile sign-update-site is set.

Change-Id: I3d508526a4cc60c9a88c6946e9e81115a5c28c30
Signed-off-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/204353
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Marc Dumais <marc.dumais@ericsson.com>
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>