[osgi] rt-transports-http should not fail during servlet unregistration

2017-08-02 09:04:23,554 | ERROR | lixDispatchQueue | cxf-rt-transports-http           | FrameworkEvent ERROR - org.apache.cxf.cxf-rt-transports-http
java.lang.IllegalArgumentException: Alias [/cxf] was never registered
	at org.ops4j.pax.web.service.internal.HttpServiceStarted.unregister(HttpServiceStarted.java:278)
	at org.ops4j.pax.web.service.internal.HttpServiceProxy.unregister(HttpServiceProxy.java:77)
	at org.apache.cxf.transport.http.osgi.ServletExporter.updated(ServletExporter.java:54)
	at org.apache.cxf.transport.http.osgi.HttpServiceTrackerCust.removedService(HttpServiceTrackerCust.java:52)
	at org.osgi.util.tracker.ServiceTracker$Tracked.customizerRemoved(ServiceTracker.java:956)
	at org.osgi.util.tracker.ServiceTracker$Tracked.customizerRemoved(ServiceTracker.java:1)
	at org.osgi.util.tracker.AbstractTracked.untrack(AbstractTracked.java:341)
	at org.osgi.util.tracker.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:902)
	at org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:943)
	at org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:794)
	at org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:544)
	at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4445)
	at org.apache.felix.framework.Felix.access$000(Felix.java:77)
	at org.apache.felix.framework.Felix$1.serviceChanged(Felix.java:404)
	at org.apache.felix.framework.ServiceRegistry.unregisterService(ServiceRegistry.java:153)
	at org.apache.felix.framework.ServiceRegistrationImpl.unregister(ServiceRegistrationImpl.java:128)
	at org.ops4j.pax.web.service.internal.Activator.updateController(Activator.java:336)
	at org.ops4j.pax.web.service.internal.Activator$2.run(Activator.java:286)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)