Deprecated the yamlutils module.

The pyyaml is now safe by default:

https://github.com/yaml/pyyaml/pull/74/files
https://access.redhat.com/security/cve/CVE-2017-18342

So the yamlutils is now useless. We can depracated it and then remove it.

Change-Id: Ibaf782786eef20d6895542e6e66ebf5befe434f0

requirements.txt

@@ -16,3 +16,4 @@ PyYAML>=3.12 # MIT
 stevedore>=1.20.0 # Apache-2.0
 six>=1.10.0 # MIT
 PrettyTable<0.8,>=0.7.2 # BSD
+debtcollector>=1.2.0 # Apache-2.0

solumclient/common/yamlutils.py

@@ -10,8 +10,13 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from debtcollector import removals
 import yaml
 
+removals.removed_module(
+    'solumclient.common.yamlutils', version='3.0.0', removal_version='4.0.0',
+    message='The solumclient.common.yamlutils will be removed')
+
 
 if hasattr(yaml, 'CSafeLoader'):
     yaml_loader = yaml.CSafeLoader