Add Loader argument to 'yaml.load' invocations as required by PyYAML 6.0.

Submitted upstream:

  https://github.com/ganeti/ganeti/pull/1668

diff --git a/qa/qa_utils.py b/qa/qa_utils.py
index da485df48..27428e685 100644
--- a/qa/qa_utils.py
+++ b/qa/qa_utils.py
@@ -450,7 +450,7 @@ def GetObjectInfo(infocmd):
   master = qa_config.GetMasterNode()
   cmdline = utils.ShellQuoteArgs(infocmd)
   info_out = GetCommandOutput(master.primary, cmdline)
-  return yaml.load(info_out)
+  return yaml.load(info_out, Loader=yaml.SafeLoader)
 
 
 def UploadFile(node, src):
diff --git a/test/py/ganeti.cli_unittest.py b/test/py/ganeti.cli_unittest.py
index 9cc980afa..242aac9fd 100755
--- a/test/py/ganeti.cli_unittest.py
+++ b/test/py/ganeti.cli_unittest.py
@@ -1141,14 +1141,15 @@ class TestFormatPolicyInfo(unittest.TestCase):
           self._RenameDictItem(minmax, key, keyparts[0])
     self.assertTrue(constants.IPOLICY_DTS in parsed)
     parsed[constants.IPOLICY_DTS] = yaml.load("[%s]" %
-                                              parsed[constants.IPOLICY_DTS])
+                                              parsed[constants.IPOLICY_DTS],
+                                              Loader=yaml.SafeLoader)
 
   @staticmethod
   def _PrintAndParsePolicy(custom, effective, iscluster):
     formatted = cli.FormatPolicyInfo(custom, effective, iscluster)
     buf = StringIO()
     cli._SerializeGenericInfo(buf, formatted, 0)
-    return yaml.load(buf.getvalue())
+    return yaml.load(buf.getvalue(), Loader=yaml.SafeLoader)
 
   def _PrintAndCheckParsed(self, policy):
     parsed = self._PrintAndParsePolicy(policy, NotImplemented, True)