Avoid dangerous file parsing and object serialization libraries.
yaml.load is the obvious function to use but it is dangerous[1]
Because yaml.load return Python object may be dangerous if you
receive a YAML document from an untrusted source such as the
Internet. The function yaml.safe_load limits this ability to
simple Python objects like integers or lists.
In addition, Bandit flags yaml.load() as security risk
so replace all occurrences with yaml.safe_load().
Thus I replace yaml.load() with yaml.safe_load()
[1]https://security.openstack.org/guidelines/dg_avoid-dangerous-input-parsing-libraries.html
Change-Id: Iaa2b7d9c880f3e20243bb2a9cbd8f9db29ecc267
15fd41725a