HAProxy: change to use option forwardfor to pass origin IP address
to backend via X-Forwarded-For header

Keystone: Apache does the audit logs for keystone.  Change the
LogFormat to display the passed address instead of the connection
address which is that of the load balancer.

Nova, Cinder, Glance: these services can make use of the address
passed in X-Forwarded-For.  With this setting the API logs for
these services include the client IP address.

Change-Id: Ia861ecc11a7c7d463d0366586926d1a842853f69
Closes-Bug: #1548935

Partially implements: blueprint heka
Change-Id: I940143876981a04464af67aff65c09a06926701d