Remove dependency fallback for Python 2

... because Python 2 is no longer supported.

Change-Id: I51ad93dd3f2303d1674c15618d08af9ac015a8a9

zaqar/storage/swift/subscriptions.py

@@ -15,10 +15,7 @@ import functools
 from oslo_serialization import jsonutils
 from oslo_utils import uuidutils
 import swiftclient
-try:  # Python3
-    from urllib.parse import quote_plus
-except ImportError:  # Python2
-    from urllib import quote_plus
+from urllib.parse import quote_plus
 
 from zaqar import storage
 from zaqar.storage import errors

zaqar/transport/websocket/driver.py

@@ -13,16 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import asyncio
 import socket
 
 from oslo_log import log as logging
 from oslo_utils import netutils
 
-try:
-    import asyncio
-except ImportError:
-    import trollius as asyncio
-
 from zaqar.common import decorators
 from zaqar.conf import drivers_transport_websocket
 from zaqar.i18n import _

zaqar/transport/websocket/protocol.py

@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import asyncio
+import email
 import datetime
 import io
 import sys
@@ -25,18 +27,6 @@ from oslo_utils import timeutils
 import pytz
 import txaio
 
-try:
-    import asyncio
-except ImportError:
-    import trollius as asyncio
-
-try:
-    import mimetools
-    Message = mimetools.Message
-except ImportError:
-    import email
-    Message = email.message_from_binary_file
-
 from zaqar.common import consts
 
 
@@ -253,7 +243,8 @@ class NotificationProtocol(asyncio.Protocol):
 
         if self._state == 'HEADERS' and b'\r\n\r\n' in self._data:
             headers, self._data = self._data.split(b'\r\n\r\n', 1)
-            headers = Message(io.BytesIO(headers))
+            headers = email.message_from_binary_file(io.BytesIO(headers))
+
             # try both cases of content-length for backwards compatibility
             length = headers.get(b'content-length',
                                  headers.get('Content-Length'))