openvz: Resolve Coverity RESOURCE_LEAK

Commit id 'a4e86390' modified the command line to allow --ipadd multiple
times, which caused Coverity to notice a latent memory leak with the
'ipAddr' string not being VIR_FREE()'d

Signed-off-by: John Ferlan <jferlan@redhat.com>

src/openvz/openvz_driver.c

@@ -911,6 +911,7 @@ openvzDomainSetNetwork(virConnectPtr conn, const char *vpsid,
         for (i = 0; i < net->nips; i++) {
             char *ipStr = virSocketAddrFormat(&net->ips[i]->address);
             virCommandAddArgList(cmd, "--ipadd", ipStr, NULL);
+            VIR_FREE(ipStr);
         }
     }