Graceful Shutdown property cannot be set on Karaf

In Camel documentation is written when is set property org.apache.camel.impl.DefaultShutdownStrategy to DEBUG level it should log some inflight information. This property can't be set. Also inflight log information appears in log without any setting property.

Test was used from jbossqe-camel-it testsuite
As first it set property named above. Then send some data to route and try to stop it. Then it checks if is inflight data in log.

You can try set this property on Karaf by this command and it fails on Karaf version fuse-karaf-7.5.0.fuse-750029:

config:edit org.ops4j.pax.logging; config:property-append log4j2.logger.org.apache.camel.impl.DefaultShutdownStrategy "DEBUG"; config:update

Camel routes from test:

		<route startupOrder="1">
			<from uri="direct:start"/>
			<log message="GracefulShutdownTest: ${body}"/>
			<to uri="file://graceful-shutdown-test/deferred"/>
		</route>

		<route startupOrder="2" shutdownRoute="Defer">
			<from uri="file://graceful-shutdown-test/deferred"/>
			<delay>
				<constant>15000</constant>
			</delay>
			<to uri="mock:result"/>
		</route>