Configure passthrough in swift config files

blueprint passthrough-config

This change adds passthrough support to swift config files:

  proxy-server.conf
  account-server.conf
  container-server.conf
  object-server.conf

If you want to add the following to proxy-server.conf:

[app:proxy-server]
sorting_method=timing

[filter:authtoken]
include_service_catalog=false

Then create a Json structure like:

{
  "swift-proxy-server":
  {"config":
    [{"section": "app:proxy-server",
      "values":
        [{"option": "sorting_method",
          "value": "timing"
         }
        ]
     },
     {"section": "filter:authtoken",
       "values":
         [{"option": "include_service_catalog",
           "value": "false"
          }
         ]
     }
    ]
  }
}

This Json structure can be injected into devtest by setting the environment
variable OVERCLOUD_EXTRA_CONFIG:

export OVERCLOUD_EXTRA_CONFIG="{\"swift-proxy-server\": {\"config\": [{\"section\": \
\"app:proxy-server\",\"values\": [{\"option\": \"sorting_method\", \"value\": \
\"timing\"}]},{\"section\": \"filter:authtoken\",\"values\": [{\"option\": \
\"include_service_catalog\", \"value\": \"false\"}]}]}}"

Change-Id: I4c332447f36f5af7ca3c6f78f41477c5e94abddf
Merge "Configure passthrough in swift config files"