Replaces yaml.load() with yaml.safe_load()
Replaces yaml.load() with yaml.safe_load()

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.

Reference:
https://security.openstack.org/guidelines/dg_avoid-dangerous-input-parsing-libraries.html

Change-Id: I9841e688e16e9bebef5eb278ee2f3a12f2ca61f4

stackforge/fuel-stats,stackforge/fuel-stats,stackforge/fuel-stats