api: remove HostConfig.LxcConf field

Commit 3b5fac462d21ca164b3778647420016315289034  / docker 1.10 removed support
for the LXC runtime, and removed the corresponding fields from the API (v1.22).

This patch removes the `HostConfig.LxcConf` field from the swagger definition.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

api/swagger.yaml

@@ -5915,7 +5915,6 @@ paths:
                       property1: "string"
                       property2: "string"
                 IpcMode: ""
-                LxcConf: []
                 Memory: 0
                 MemorySwap: 0
                 MemoryReservation: 0