Changes

releng: Fix SLF4J logging for staging platform

The bundle slf4j.simple is no longer a fragment of slf4j.api like
org.slf4j.binding.simple was in SLF4J 1.7.30. As a consequence, the
fragment org.eclipse.tracecompass.slf4j.binding.simple.properties must
set slf4j.simple as its Fragment-Host because it is this plugin's class
loader that will attempt to find the simplelogger.properties resource.

In order for org.slf4j.simple.SimpleServiceProvider to be found by the
ServiceLoader, plugins org.apache.aries.spifly.dynamic.bundle and
slf4j.simple must have their autoStart set to "true" in the
swtbot-test-plugin profile.

For manual testing the user will need to manually set the Auto-Start to
"true" for these two plugins in the JUnit Plug-in Test Run/Debug
Configuration in Eclipse.

Change-Id: I4a325248c1c5952e41fb0e4c3fb1d8163a631e90
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>