fix bridge interface pxe boot case get incorrect gateway

   in teardown function, the utils_net.delete_linux_bridge_tmux should use iface_name var to
make host interface get ip by dhclient
Signed-off-by: nanli <[email protected]>

Author: nanli1

libvirt/tests/src/virtual_network/rom/iface_rom_disable_pxe_boot.py

@@ -60,7 +60,7 @@ def teardown_test():
         Clean up test environment
         """
         test.log.debug("TEST_TEARDOWN: Recover the env.")
-        utils_net.delete_linux_bridge_tmux(bridge_name, host_iface)
+        utils_net.delete_linux_bridge_tmux(bridge_name, iface_name)
         bkxml.sync()
 
     vm_name = guest_os.get_vm(params)