Fix iam_policies integration test

The test was failing in the configuration validation phase because no
base_os was specified and this parameter does no longer has a default
value.

Signed-off-by: ddeidda <[email protected]>

Author: ddeidda

tests/integration-tests/tests/iam_policies/test_iam_policies.py

@@ -21,6 +21,8 @@
 @pytest.mark.regions(["us-east-1"])
 @pytest.mark.schedulers(["sge", "awsbatch"])
 @pytest.mark.skip_instances(["g3.8xlarge"])
+@pytest.mark.os(["alinux2"])
+@pytest.mark.usefixtures("os")
 def test_iam_policies(region, scheduler, pcluster_config_reader, clusters_factory):
     """Test IAM Policies"""
     cluster_config = pcluster_config_reader(