Fix build on python3.

dulwich/client.py

@@ -1166,7 +1166,7 @@ def default_user_agent_string():
 def default_urllib2_opener(config):
     if config is not None:
         try:
-            proxy_server = config.get("http", "proxy")
+            proxy_server = config.get(b"http", b"proxy")
         except KeyError:
             proxy_server = None
     else:
@@ -1177,7 +1177,7 @@ def default_urllib2_opener(config):
     opener = urllib2.build_opener(*handlers)
     if config is not None:
         try:
-            user_agent = config.get("http", "useragent")
+            user_agent = config.get(b"http", b"useragent")
         except KeyError:
             user_agent = None
     else:

dulwich/tests/test_client.py

@@ -940,6 +940,5 @@ class DefaultUrllib2OpenerTest(TestCase):
         config = ConfigDict()
         config.set(b'http', b'proxy', b'http://localhost:3128/')
         opener = default_urllib2_opener(config=config)
-        self.assertTrue(
-                any([isinstance(handler, urllib2.ProxyHandler)
-                    for handler in opener.handlers]))
+        self.assertIn(urllib2.ProxyHandler,
+                      list(map(lambda x: x.__class__, opener.handlers)))