Changes

releng: Build with tracecompass-e4.28 target by default

Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Change-Id: Idbfff22c895400871dcab3d7f8e574bbd2aae1ce
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/201630
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>