Cleanup i18n marker functions to match Oslo usage

Define marker functions as per usage in documentation.
http://docs.openstack.org/developer/oslo.i18n/usage.html

Change-Id: I564f5d1f31314be5c18420b6bc3d694a561d78f2

tox.ini

@@ -79,7 +79,7 @@ exclude = .venv*,.git,.tox,dist,doc,*lib/python*,*.egg,.update-venv
 max-complexity = 16
 
 [hacking]
-import_exceptions = zaqar.i18n._
+import_exceptions = zaqar.i18n
 
 [testenv:install-guide]
 # NOTE(jaegerandi): this target does not use constraints because

zaqar/common/urls.py

@@ -20,10 +20,7 @@ import hmac
 from oslo_utils import timeutils
 import six
 
-from zaqar import i18n
-
-
-_LE = i18n._LE
+from zaqar.i18n import _LE
 
 _DATE_FORMAT = '%Y-%m-%dT%H:%M:%S'
 

zaqar/transport/wsgi/v2_0/urls.py

@@ -18,13 +18,11 @@ from oslo_log import log as logging
 import six
 
 from zaqar.common import urls
-from zaqar import i18n
+from zaqar.i18n import _LE
 from zaqar.transport import utils
 from zaqar.transport.wsgi import errors as wsgi_errors
 from zaqar.transport.wsgi import utils as wsgi_utils
 
-_ = i18n._
-_LE = i18n._LE
 LOG = logging.getLogger(__name__)
 
 _KNOWN_KEYS = {'methods', 'expires', 'paths'}