Do not use PyYAML 5+ version
Do not use PyYAML 5+ version

Error in 5+:
YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.

Change-Id: I335c60ea2b4eea4d795e37baa93e66e4c282592b

dis-xcom/reclass_tools,dis-xcom/reclass_tools