Typo fix

theano/sandbox/cuda/opt.py

@@ -40,7 +40,7 @@ optdb.register('gpu_opt',
                optdb.__position__.get('add_destroy_handler', 49.5) - 1,
                'gpu', 'fast_run')
 # This second pass is needed as the fusion can put all the non float32 code
-# inside the elemwise. When it there is no float64 op, this is working.
+# inside the elemwise. When there is no float64 op, this is working.
 optdb.register('gpu_after_fusion',
                ProxyDB(gpu_seqopt),
                optdb.__position__.get('elemwise_fusion', 71) + .1,