node_device_hal.c: Follow _class -> klass rename

In 0eca80e6 _class was renamed to klass for variety of struct
members. However, gather_usb_cap() was missed out in this rename
leaving FreeBSD build broken.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/node_device/node_device_hal.c

@@ -171,7 +171,7 @@ gather_usb_cap(LibHalContext *ctx, const char *udi,
     (void)get_int_prop(ctx, udi, "usb.interface.number",
                        (int *)&d->usb_if.number);
     (void)get_int_prop(ctx, udi, "usb.interface.class",
-                       (int *)&d->usb_if._class);
+                       (int *)&d->usb_if.klass);
     (void)get_int_prop(ctx, udi, "usb.interface.subclass",
                        (int *)&d->usb_if.subclass);
     (void)get_int_prop(ctx, udi, "usb.interface.protocol",