modify init value of mean square in rmsprop optimizer

mindspore/nn/optim/rmsprop.py

@@ -174,7 +174,7 @@ class RMSProp(Optimizer):
             self.opt = P.ApplyRMSProp(use_locking)
 
         self.momentum = momentum
-        self.ms = self.parameters.clone(prefix="mean_square", init='zeros')
+        self.ms = self.parameters.clone(prefix="mean_square", init='ones')
         self.moment = self.parameters.clone(prefix="moment", init='zeros')
         self.hyper_map = C.HyperMap()
         self.epsilon = epsilon