This sets up the HTTPProxyToWSGI middleware in front of Nova-API. The
purpose of thise middleware is to set up the request URL correctly in
case there is a proxy (For instance, a loadbalancer such as HAProxy)
in front of Nova.
So, for instance, when TLS connections are being terminated in the
proxy, and one tries to get the versions from the / resource of
Nova, one will notice that the protocol is incorrect; It will show
'http' instead of 'https'. So this middleware handles such cases.
Thus helping Keystone discovery work correctly.
The HTTPProxyToWSGI is off by default and needs to be enabled via a
configuration value.
Change-Id: Ia78f73e96585ab33a379a0b0be6d9682f7fbd810
Closes-Bug: #1573766
b609a3b32e