OSGi configuration. Using now the correct MBean in hawtio-show directive...

.... Fixes #1623
@paoloantinori - this should remain as `{{configAdminMBean}}`. There is no delete method on hawtioConfigAdminMBean, only `configAdminUpdate` method. See https://github.com/hawtio/hawtio/blob/a16d6d1697f5dafd53b10f671c26f52cd3811b13/hawtio-osgi-jmx/src/main/java/io/hawt/osgi/jmx/ConfigAdmin.java#L40.