clarify error message.

theano/sandbox/cuda/__init__.py

@@ -500,7 +500,7 @@ def use(device,
     """
     global cuda_enabled, cuda_initialization_error_message
     _logger.warn("The cuda backend is deprecated and will be removed in "
-                 "the next release.  Please switch to the gpuarray backend. "
+                 "the next release (v0.10).  Please switch to the gpuarray backend. "
                  "You can get more information about how to switch at this "
                  "URL:\n https://github.com/Theano/Theano/wiki/Converting-to-the-new-gpu-back-end%28gpuarray%29\n")
     if force and not cuda_available and device.startswith('gpu'):