[Rust] Generated models compiler warnings

Description

I encountered two issues with rust generator ('rust' one, not 'rust-server'). I generated models for Docker API.

Problems:

1. Uppercase fields and variables:

BuildCache:
    type: "object"
    properties:
      ID:
        type: "string"
    ...

gives

#[derive(Debug, Serialize, Deserialize)]
pub struct BuildCache {
    #[serde(rename = "ID")]
    ID: Option<String>,
    ...
}

getters, setters etc. of this field also have uppercase ID. It results with many compiler warnings.

2. Double underscore.

LogConfig:
  type: "object"
  description: "The logging configuration for this container"
  properties:
    Type:
      type: "string"
      enum:
        - "json-file"
        - "syslog"
        - "journald"
        - "gelf"
        ...

produces

#[derive(Debug, Serialize, Deserialize)]
pub struct HostConfigLogConfig {
    #[serde(rename = "Type")]
    _type: Option<String>,
    ...
}

Problem is that names for _type methods have incorrect names for rust: set__type, get__type. Maybe it should be _set_type insted.

Swagger-codegen version

2.3.1

Start with the Rust generator's model generation path and reproduce the reported output using the Docker API models. Verify generated field and accessor names for uppercase properties and the Type property, with completion shown by warning-free Rust output and corrected setter/getter names.