[GSS](7.1.0) jgroups port_range documentation

Document URL:
https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.1.beta/html-single/configuration_guide/

Section Number and Name:
22.2.3. Configure TCPPING

Describe the issue:

port_range is initialport + port_range, as explained here
http://www.jgroups.org/manual/html/user-advanced.html

Suggestions for improvement:

Additionally, the description of the initial_hosts property in the EAP
documentation is incomplete/misleading:
"A comma-separated list of the hosts which are considered well-known,
and will be available to look up the initial membership."

The value of the initial_hosts property includes a host and port
using the syntax: host[port]. The port_range applies to each address
specified in initial_hosts. The end result is that the port_range
effectively multiplies the set of potential initial members.
e.g.
if initial_hosts="host1[1000],host2[2000]" and port_range="2", TCPPING
will try to contact the following addresses when the channel is
connected:

host1:1000, host1:1001, host1:1002, host2:2000, host2:2001, host2:2002