Fixes for parallel code on Python 3.

IPython/parallel/apps/ipcontrollerapp.py

@@ -273,7 +273,7 b' class IPControllerApp(BaseParallelApplication):'
         if not self.reuse_files:
             # save to new json config files
             f = self.factory
-            cdict = {'exec_key' : f.session.key,
+            cdict = {'exec_key' : f.session.key.decode('ascii'),
                     'ssh' : self.ssh_server,
                     'url' : "%s://%s:%s"%(f.client_transport, f.client_ip, f.regport),
                     'location' : self.location

IPython/utils/traitlets.py

@@ -961,7 +961,7 b' class CComplex(Complex):'
 class Bytes(TraitType):
     """A trait for byte strings."""
 
-    default_value = ''
+    default_value = b''
     info_text = 'a string'
 
     def validate(self, obj, value):