Inconsistency when using IP addresses during gluster peer probe

[dahorak]

When Gluster Trusted Storage Pool is created using IP addresses (not hostnames), Grafana lists each host twice - by hostname and by IP address.

Steps to Reproduce:

1. Prepare Gluster Cluster, use IP addresses in gdeploy configuration file (instead of hostnames):
   Example gdeploy configuration file:

   [hosts]
   192.0.2.1
   192.0.2.2
   192.0.2.3
   192.0.2.4
   192.0.2.5
   192.0.2.6
   
   [peer]
   action=probe
   ignore_peer_errors=no
   

2. Install and configure Tendrl Server and Tendrl Node Agents.

3. Import Gluster Cluster into Tendrl.

4. Open Grafana Tendrl-Gluster-Hosts dashboard.

Actual results:
Host Name selectbox contains each server twice, once listed by Hostname, second time listed by IP.

Expected results:
Hosts should be listed only once by Hostname.

See also https://bugzilla.redhat.com/show_bug.cgi?id=1512937 and #360