2014-04-24  Shilpa Shri  <shilpa.shri@samsung.com>

        Make WebCLCommandQueue parameters properly nullable
        Issue #510

        Reviewed by NOBODY (OOPS!).

        Missed out for enqueueWriteBuffer API.

        Conformance test :
        conformance/bindingTesting/queues/cl_commandQueue_enqueueWriteBuffer.html

        * Modules/webcl/WebCLCommandQueue.idl: