[protoc-gen-php] Enum default values: case mismatch

[MonkeyMaster]

Enum items are converted to upper case in constant definitions while remain in camel case in default values.

enum DocumentType {
    UnknownDocumentType = -1;
...

<?php
 * @enum Diadoc.Api.Proto.Documents.DocumentType
 */
class Diadoc_Api_Proto_Documents_DocumentType
{
  const UNKNOWNDOCUMENTTYPE = -1;

...

      $desc->addField(6, new ProtocolBuffersFieldDescriptor(array(
        "type"     => ProtocolBuffers::TYPE_ENUM,
        "name"     => "DocumentType",
        "required" => false,
        "optional" => true,
        "repeated" => false,
        "packable" => false,
        "default"  => Diadoc_Api_Proto_Documents_DocumentType::UnknownDocumentType,
      )));