Represent a NONE log with a blank string (client can detect that as a nonpath).

src/supervisor/rpcinterface.py

@@ -654,7 +654,7 @@ class SupervisorNamespaceRPCInterface:
         state = process.get_state()
         spawnerr = process.spawnerr or ''
         exitstatus = process.exitstatus or 0
-        logfile = process.config.stdout_logfile or 'NONE'
+        logfile = process.config.stdout_logfile or ''
 
         info = {
             'name':process.config.name,

src/supervisor/tests/test_rpcinterfaces.py

@@ -749,7 +749,7 @@ class SupervisorNamespaceXMLRPCInterfaceTests(TestBase):
         interface = self._makeOne(supervisord)
         data = interface.getProcessInfo('foo')
 
-        self.assertEqual(data['logfile'], 'NONE')
+        self.assertEqual(data['logfile'], '')
 
     def test_getAllProcessInfo(self):
         from supervisor.process import ProcessStates