Add HTTP PATCH support

Author: friedfilibuster

google-http-client-appengine/src/main/java/com/google/api/client/extensions/appengine/http/UrlFetchTransport.java

@@ -62,7 +62,8 @@ enum CertificateValidationBehavior {
  * order.
  */
  private static final String[] SUPPORTED_METHODS =
- {HttpMethods.DELETE, HttpMethods.GET, HttpMethods.HEAD, HttpMethods.POST, HttpMethods.PUT};
+ {HttpMethods.DELETE, HttpMethods.GET, HttpMethods.HEAD, HttpMethods.POST,
+ HttpMethods.PUT, HttpMethods.PATCH};
  static {
  Arrays.sort(SUPPORTED_METHODS);
  }
@@ -119,6 +120,8 @@ protected UrlFetchRequest buildRequest(String method, String url) throws IOExcep
  httpMethod = HTTPMethod.HEAD;
  } else if (method.equals(HttpMethods.POST)) {
  httpMethod = HTTPMethod.POST;
+ } else if (method.equals(HttpMethods.PATCH)) {
+ httpMethod = HTTPMethod.PATCH;
  } else {
  httpMethod = HTTPMethod.PUT;
  }