stream: fix ip allocation, nginx configuration

- Lvs role needed to be fixed as well to move IPs to the new LVS servers
- We did not have a rewrite to manage non-standard location directives
  in the nginx configuration, so the rcstream software would not respond correctly.

Change-Id: Ia99377eca014cc951bcf08db9100d8a5852002eb
Signed-off-by: Giuseppe Lavagetto <glavagetto@wikimedia.org>