Remove deprecated GeoJsonDataSource parameter

Fixes #2257

Author: mramato

CHANGES.md

@@ -6,7 +6,8 @@ Change Log
 * Breaking changes
   * `Rectangle.intersectWith` was deprecated in Cesium 1.5. Use `Rectangle.intersection`, which is the same but returns `undefined` when two rectangles do not intersect.
   * `Rectangle.isEmpty` was deprecated in Cesium 1.5.
-  
+  * The `sourceUri` parameter to `GeoJsonDatasource.load` was deprecated in Cesium 1.4 and has been removed. Use options.sourceUri instead.
+
 ### 1.5 - 2015-01-05
 
 * Breaking changes

Source/DataSources/GeoJsonDataSource.js

@@ -6,7 +6,6 @@ define([
         '../Core/defaultValue',
         '../Core/defined',
         '../Core/defineProperties',
-        '../Core/deprecationWarning',
         '../Core/DeveloperError',
         '../Core/Event',
         '../Core/getFilenameFromUri',
@@ -32,7 +31,6 @@ define([
         defaultValue,
         defined,
         defineProperties,
-        deprecationWarning,
         DeveloperError,
         Event,
         getFilenameFromUri,
@@ -776,19 +774,12 @@ define([
         }
         //>>includeEnd('debug');
 
-        var sourceUri = options;
-        if (typeof options === 'string') {
-            sourceUri = options;
-            deprecationWarning('GeoJsonDataSource.load', 'GeoJsonDataSource.load now takes an options object instead of a string as its second parameter.  Support for passing a string parameter will be removed in Cesium 1.6');
-        } else if (defined(options)) {
-            sourceUri = options.sourceUri;
-        }
-
-        return load(this, geoJson, sourceUri, options);
+        return load(this, geoJson, undefined, options);
     };
 
     function load(that, geoJson, sourceUri, options) {
         options = defaultValue(options, defaultValue.EMPTY_OBJECT);
+        sourceUri = defaultValue(sourceUri, options.sourceUri);
 
         options = {
             markerSize : defaultValue(options.markerSize, defaultMarkerSize),