Merge pull request #3359 from zxcd/clean_fluid

[ASR] clean fluid 

paddlespeech/s2t/training/optimizer/adadelta.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import paddle
-from paddle.fluid import framework
+from paddle import framework
 from paddle.optimizer import Optimizer
 
 __all__ = []