Cleanup HornetQ xsd files in "docs/schema" directory

The download zip for WildFly 10.0CR4 contains the xsd files for HornetQ messaging configurations in "docs/schema". Those are obsoleted by ActiveMQ and should be removed.

-jboss-as-messaging-deployment_1_0.xsd (deployment of a "-jms.xml" file according to this old schema will fail with an error anyway), replaced by "wildfly-messaging-activemq-deployment_1_0.xsd")
-jboss-as-messaging_x_y.xsd (server configuration files, replaced by "wildfly-messaging-activemq_1_0.xsd").