Fix issue with LSTM state variables initialization

Author: buddhapuneeth

tf2onnx/rewriter/lstm_rewriter_base.py

@@ -49,9 +49,6 @@ class LSTMRewriterBase(UnitRnnRewriterBase):
 
     def __init__(self, g):
         super(LSTMRewriterBase, self).__init__(g)
-        # {var_name: (finder, connector)}
-        self.state_variable_handler = list()
-        self.state_variable_handlers = list()
 
     def create_context(self):
         return LSTMContext()
@@ -66,6 +63,8 @@ def parse_unit_rnn(self, context):
         5 attributes, e.g., activation_alpha, activation_beta... optional
         """
         logger.debug("parse unit rnn")
+        self.state_variable_handler = list()
+        self.state_variable_handlers = list()
 
         logger.debug("match unit cell against loop body graph")
         cell_match = self.find_cell(context)