py3: fix http_main changes for py3

vcsserver/http_main.py

@@ -25,7 +25,7 b' import wsgiref.util'
 import traceback
 import tempfile
 from itertools import chain
-from cStringIO import StringIO
+from io import StringIO
 
 import simplejson as json
 import msgpack
@@ -89,7 +89,7 b' def _int_setting(settings, name, default'
 
 def _bool_setting(settings, name, default):
     input_val = settings.get(name, default)
-    if isinstance(input_val, unicode):
+    if isinstance(input_val, str):
         input_val = input_val.encode('utf8')
     settings[name] = asbool(input_val)
     return settings[name]
@@ -209,7 +209,7 b' class VCSViewPredicate(object):'
         self.remotes = val
 
     def text(self):
-        return 'vcs view method = %s' % (self.remotes.keys(),)
+        return 'vcs view method = %s' % (list(self.remotes.keys()),)
 
     phash = text
 
@@ -497,7 +497,7 b' class HTTPApplication(object):'
         except Exception:
             log.exception('Failed to read .ini file for display')
 
-        environ = os.environ.items()
+        environ = list(os.environ.items())
 
         resp = {
             'id': payload.get('id'),