* adding support for loopback interface
currently the loopback interface lo is not supported with vyos_l3_interface, this commit fixes that. Right now there is a limit of loopback interfaces to just lo, if you want more interfaces you need to use a dummy interface https://wiki.vyos.net/wiki/Dummy_interfaces
* fixing spacing as per pep8 test
fixing issues for sanity test
* ugh, missed on spacing issue
* getting rid of continuation lines, the CI system does not like it
(cherry picked from commit a52a7d2065)