Replace oslo_utils.encodeutils.exception_to_unicode (again)

The function is deprecated because it is equivalent to str(ex) in
Python 3.

Fix a few remaining usages which were overlooked by the previous
attempt[1].

[1] 8331446fa4

Change-Id: I8915500f49f3bd13b848da2709658da533d14cfe
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

trove/guestagent/datastore/mysql_common/service.py

@@ -17,7 +17,6 @@ import os
 import re
 
 from oslo_log import log as logging
-from oslo_utils import encodeutils
 import sqlalchemy
 from sqlalchemy import event
 from sqlalchemy import exc
@@ -210,11 +209,9 @@ class BaseMySqlAdmin(object, metaclass=abc.ABCMeta):
             user.check_reserved()
         except ValueError as ve:
             LOG.exception("Error Getting user information")
-            err_msg = encodeutils.exception_to_unicode(ve)
-            raise exception.BadRequest(_("Username %(user)s is not valid"
-                                         ": %(reason)s") %
-                                       {'user': username, 'reason': err_msg}
-                                       )
+            raise exception.BadRequest(
+                _("Username %(user)s is not valid: %(reason)s") %
+                {'user': username, 'reason': ve})
         with mysql_util.SqlClient(
                 self.mysql_app.get_engine(), use_flush=True) as client:
             q = sql_query.Query()

trove/guestagent/module/driver_manager.py

@@ -15,7 +15,6 @@
 #
 
 from oslo_log import log as logging
-from oslo_utils import encodeutils
 import stevedore
 
 from trove.common import base_exception as exception
@@ -71,8 +70,7 @@ class ModuleDriverManager(object):
                 LOG.info("Driver '%s' not supported, skipping",
                          driver.get_type())
         except AttributeError as ex:
-            LOG.exception("Exception loading module driver: %s",
-                          encodeutils.exception_to_unicode(ex))
+            LOG.exception("Exception loading module driver: %s", ex)
 
         return supported