Use call_and_ignore_notfound_exc to cleanup floating-ip-bulk

The _delete_floating_ips_bulk in FloatingIPsBulkAdminTestJSON
should only ignore the exception silently when the exception type is
NotFound, so here we can just use test_utils.call_and_ignore_notfound_exc.

Change-Id: I2e3c4e30650b22a1b20497d26842414126ce6b25
1 file changed