Added x-forwarded-proto support for https incase of loadbalanced env

Added  support for https in loadbalanced environment. 
If all the requests from loadbalancer are mapped to http, we can not differentiate the client request based on the scheme.  Server variable $http_x_forwarded_porto comes to our
 rescue.

![nginx https in loadbalanced env](https://f.cloud.github.com/assets/837733/289306/d17e7790-92a4-11e2-9524-f8931dc7ef70.jpg)