Fixes unicode logging decoding issue

Logging fails with an exception when unicode conversion of the message
cannot be performed.

This includes also Exception objects, where the exception message has
an unknown encoding.

The calling code should be responsible for handling the unicode encoding, but
nevertheless, the logging module should handle this scenario and not raise
an exception.

Closes-Bug: #1393870

Change-Id: Ied46e4a8715d11a3cf59d651004e17f6fe4c760b

cloudbaseinit/openstack/common/log.py

@@ -307,7 +307,11 @@ class ContextAdapter(BaseLoggerAdapter):
         #                before it can get to the python logging and
         #                possibly cause string encoding trouble
         if not isinstance(msg, six.text_type):
-            msg = six.text_type(msg)
+            try:
+                msg = six.text_type(msg)
+            except UnicodeDecodeError:
+                # Unknown encoding. Let the Python logging module handle it
+                pass
 
         if 'extra' not in kwargs:
             kwargs['extra'] = {}