virsh-interface: Unify list column alignment

Before:

$ virsh iface-list
Name                 State      MAC Address
--------------------------------------------
br0                  active     f0:de:f1:dc:b8:b0
virbr2               active     52:54:00:61:78:0c

After:

$ virsh iface-list
 Name                 State      MAC Address
---------------------------------------------------
 br0                  active     f0:de:f1:dc:b8:b0
 virbr2               active     52:54:00:61:78:0c

tools/virsh-interface.c

@@ -360,14 +360,14 @@ cmdInterfaceList(vshControl *ctl, const vshCmd *cmd ATTRIBUTE_UNUSED)
     if (!(list = vshInterfaceListCollect(ctl, flags)))
         return false;
 
-    vshPrintExtra(ctl, "%-20s %-10s %s\n", _("Name"), _("State"),
+    vshPrintExtra(ctl, " %-20s %-10s %s\n", _("Name"), _("State"),
                   _("MAC Address"));
-    vshPrintExtra(ctl, "--------------------------------------------\n");
+    vshPrintExtra(ctl, "---------------------------------------------------\n");
 
     for (i = 0; i < list->nifaces; i++) {
         virInterfacePtr iface = list->ifaces[i];
 
-        vshPrint(ctl, "%-20s %-10s %s\n",
+        vshPrint(ctl, " %-20s %-10s %s\n",
                  virInterfaceGetName(iface),
                  virInterfaceIsActive(iface) ? _("active") : _("inactive"),
                  virInterfaceGetMACString(iface));