Fix Javascript error

14:56:58.398 webqt.js:747 Uncaught ReferenceError: context is not defined
    at WebGLRenderingContext.gl.uniform3fv (webqt.js:747)
    at execGL (webqt.js:944)
    at handleGlesMessage (webqt.js:1088)
    at handleBinaryMessage (webqt.js:1073)
    at WebSocket.socket.onmessage (webqt.js:1129)

Change-Id: Ifa77c853b4cec29f21cc19ffc5b86b741d8ef5ab
Reviewed-by: Edward Welbourne <[email protected]>

Author: jsfdez

src/plugins/platforms/webgl/webqt.jsx

@@ -742,7 +742,7 @@ window.onload = function () {
 
         gl._uniform3fv = gl.uniform3fv;
         gl.uniform3fv = function(location, count) {
-            var d = contextData[context];
+            var d = contextData[currentContext];
             var data = [];
             for (var i = 0; i < count * 3; ++i)
                 data.push(arguments[i + 2]);