Kafka Connect S2I cluster reconciliation shouldn't be triggered on Kubernetes

[scholzj]

Cluster Controller currently triggers reconciliation of Kafka Connect S2I clusters even on Kubernetes. That seems to cause NPE:

2018-03-06 08:57:22 INFO  ClusterController:87 - Triggering periodic reconciliation for namespace default...
Mar 06, 2018 8:57:22 AM io.vertx.core.impl.ContextImpl
SEVERE: Unhandled exception
java.lang.NullPointerException
	at io.strimzi.controller.cluster.operations.cluster.KafkaConnectS2IClusterOperations.getResources(KafkaConnectS2IClusterOperations.java:275)
	at io.strimzi.controller.cluster.operations.cluster.AbstractClusterOperations.reconcileAll(AbstractClusterOperations.java:317)
	at io.strimzi.controller.cluster.ClusterController.reconcile(ClusterController.java:203)
	at io.strimzi.controller.cluster.ClusterController.lambda$null$0(ClusterController.java:88)
	at io.vertx.core.impl.VertxImpl$InternalTimerHandler.handle(VertxImpl.java:870)
	at io.vertx.core.impl.VertxImpl$InternalTimerHandler.handle(VertxImpl.java:829)
	at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:344)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:403)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463)
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858)
	at java.lang.Thread.run(Thread.java:748)

S2I reconciliation should be triggered only on OpenShift.