Handle proxying for the new Kibana 3 milestone 5

Kibana 3 Milestone 5 handles the requests to ElasticSearch a bit different
from the way older versions did. More info about that change can be found
here:

https://github.com/elasticsearch/kibana/commit/629705ea448ce4dc2838f32f95183ab25d3242ea

This change broke Kibana when sending queries through an (nginx|apache) proxy; no
graphs or data were shown at all.

I found that adding a proxy for /.*/_aliases resolved this issue.