Fix NOX breakage

Controllers are no longer namespace-able, and all calls need one fewer
arg.

Also use more sensible temporary variable name.

mininet/net.py

@@ -187,10 +187,10 @@ class Mininet( object ):
     def addController( self, controller ):
         """Add controller.
            controller: Controller class"""
-        controller = self.controller( 'c0', self.inNamespace )
-        if controller:  # allow controller-less setups
-            self.controllers.append( controller )
-            self.nameToNode[ 'c0' ] = controller
+        controller_new = self.controller( 'c0' )
+        if controller_new:  # allow controller-less setups
+            self.controllers.append( controller_new )
+            self.nameToNode[ 'c0' ] = controller_new
 
     # Control network support:
     #

mininet/node.py

@@ -661,10 +661,10 @@ class NOX( Controller ):
         """Init.
            name: name to give controller
            noxArgs: list of args, or single arg, to pass to NOX"""
-        if type( noxArgs ) != list:
-            noxArgs = [ noxArgs ]
         if not noxArgs:
             noxArgs = [ 'packetdump' ]
+        elif type( noxArgs ) != list:
+            noxArgs = [ noxArgs ]
 
         if 'NOX_CORE_DIR' not in os.environ:
             exit( 'exiting; please set missing NOX_CORE_DIR env var' )