message: Allow non-TableInitializerBases as table initializers again
diff: @@ -161,7 +161,9 @@ class InitializableLookupTableBase(LookupInterface):
  self._default_value = ops.convert_to_tensor(
  default_value, dtype=self._value_dtype)
  self._default_value.get_shape().merge_with(tensor_shape.scalar())
  - self._initializer = self._track_checkpointable(initializer, "_initializer")
  + if isinstance(initializer, checkpointable_base.CheckpointableBase):
  + self._initializer = self._track_checkpointable(
  + initializer, "_initializer")
  self._resource_handle = self.create_resource()
  self._init_op = self.initialize()
  