Allow web socket over nginx https connection

Testing: Used html from Deepak/Rahul that subscribed to
ambient temp sensor and verified the events showed up in
the web socket via my browser console.

Resolves openbmc/openbmc#2881
Resolves openbmc/openbmc#925

Change-Id: I606a68de7b5c76ae6253dc1722d087e953b7ca8b
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/recipes-httpd/nginx/files/nginx.conf b/recipes-httpd/nginx/files/nginx.conf
index d788fd2..c945544 100644
--- a/recipes-httpd/nginx/files/nginx.conf
+++ b/recipes-httpd/nginx/files/nginx.conf
@@ -70,6 +70,11 @@
                 # the journal. Nginx then uses the 127.0.0.1 and everything
                 # works fine but want to avoid the error msg to the log.
                 proxy_pass http://127.0.0.1:8081/;
+
+                # WebSocket support
+                proxy_http_version 1.1;
+                proxy_set_header Upgrade $http_upgrade;
+                proxy_set_header Connection "upgrade";
         }
         location ~ (/org/openbmc/control/flash/bmc/action/update|/upload/image|/download/dump) {
                  # Marked as 32MB to allow for firmware image updating and dump