This reverts commit dd66f235ec.
This changed the core servers API without doing it as an API extension,
so it's not an acceptable change as written.
Change-Id: I3787060583de1371e366647d38d69f37746317d5
* Servers in certain states will have network_info but it may change,
(eg. rescheduled build on another host). The extension allows the
operator to hide the address information in those states
* Fixes bug LP 1089092
Change-Id: Ie843e34a41c77903b201b45c5b67a6f75334cb5e