tools: Fix typo generating adapter_wwpn field

https://bugzilla.redhat.com/show_bug.cgi?id=1601377

Fix typo from commit id d45bee44 for the parent_wwpn field
resulting in parent_wwnn being printed twice.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

tools/virsh-pool.c

@@ -371,7 +371,7 @@ virshBuildPoolXML(vshControl *ctl,
             if (adapterParent)
                 virBufferAsprintf(&buf, " parent='%s'", adapterParent);
             else if (adapterParentWwnn && adapterParentWwpn)
-                virBufferAsprintf(&buf, " parent_wwnn='%s' parent_wwnn='%s'",
+                virBufferAsprintf(&buf, " parent_wwnn='%s' parent_wwpn='%s'",
                                   adapterParentWwnn, adapterParentWwpn);
             else if (adapterParentFabricWwn)
                 virBufferAsprintf(&buf, " parent_fabric_wwn='%s'",