Revert "Skip test_list_server_addresses if neutron"

This reverts commit 3c7f98f0b78444e3cfc411a331d40ceb07629c21.

Since blueprint admin-event-callback-api in Icehouse we shouldn't
have this issue so enable the test again.

Change-Id: I21aa94068129b856e6a2965ac749c414b8b0cc9e
Closes-Bug: #1210483
Merge "Revert "Skip test_list_server_addresses if neutron""