Stringify node_info.uuid as a precaution

Currently, utils:processing_logger_prefix() assumes node_info.uuid to be a
string.  However, a (broken) test case could encounter a TypeError logging:

   File "ironic_inspector/utils.py", line 103, in processing_logger_prefix
     return _('[node: %s]') % ' '.join(parts)
 TypeError: sequence item 0: expected string, MagicMock found

The patch purpose is to apply str(node_info.uuid) as a precaution.  This may
also help track where the real issue is with a broken test case.

Change-Id: I689f67c44a6304f7b296829fef3339872a4f6d36

ironic_inspector/test/test_utils.py

@@ -243,6 +243,11 @@ class TestProcessingLogger(base.BaseTest):
                          utils.processing_logger_prefix(node_info=node_info,
                                                         data=data))
 
+    def test_prefix_uuid_not_str(self):
+        node_info = mock.Mock(uuid=None)
+        self.assertEqual('[node: None]',
+                         utils.processing_logger_prefix(node_info=node_info))
+
     def test_adapter_no_bmc(self):
         CONF.set_override('log_bmc_address', False, 'processing')
         node_info = mock.Mock(uuid='NNN')

ironic_inspector/utils.py

@@ -88,7 +88,7 @@ def processing_logger_prefix(data=None, node_info=None):
     data = data or {}
 
     if node_info is not None:
-        parts.append(node_info.uuid)
+        parts.append(str(node_info.uuid))
 
     pxe_mac = get_pxe_mac(data)
     if pxe_mac: