When you create a Lambda permission you send the __statement id__ as mandatory parameter.

https://docs.aws.amazon.com/lambda/latest/dg/API_AddPermission.html#API_AddPermission_RequestSyntax

However this id is generated by a random value. 

https://github.com/localstack/localstack/blob/b3917bf248b77ced8ef80a3d5c0561960066db5d/localstack/services/awslambda/lambda_api.py#L927

Due to this problem, the tools like Terraform or Ansible fail when it has to be retrieved to check the existence of this element.

If you agree I could make a PR with the fix and its test.
load_file(TEST_LAMBDA_ENV), get_content=True,
            libs=TEST_LAMBDA_LIBS, runtime=LAMBDA_RUNTIME_PYTHON27)
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_ENV, zip_file=zip_file,
            runtime=LAMBDA_RUNTIME_PYTHON27, envvars=vars)
        
        result = self.lambda_client.invoke(
            FunctionName=TEST_LAMBDA_NAME_ENV, Payload=b'{}')
        result_data = result['Payload']
        self.assertEqual(result['StatusCode'], 200)
        self.assertDictEqual(json.load(result_data), vars)
        
        result = self.lambda_client.get_function_configuration(
            FunctionName=TEST_LAMBDA_NAME_ENV)
        self.assertEqual(result['Environment'], {'Variables': vars})
        
        testutil.delete_lambda_function(TEST_LAMBDA_NAME_ENV)
    def test_invocation_with_qualifier(self):
        lambda_name = 'test_lambda_%s' % short_uid()
        bucket_name = 'test-bucket-lambda2'
        bucket_key = 'test_lambda.zip'
        
        zip_file = testutil.create_lambda_archive(
            load_file(TEST_LAMBDA_PYTHON),
            get_content=True,
            libs=TEST_LAMBDA_LIBS,
            runtime=LAMBDA_RUNTIME_PYTHON27
        )
        self.s3_client.create_bucket(Bucket=bucket_name)
        self.s3_client.upload_fileobj(