Don't clean up links that may have been dumped into root NS.

This should rarely happen - in the usual case, either the
links will be shut down by Mininet.stop(), or the interfaces
will be deleted by node.stop( deleteIntfs=True ), or the
links or interfaces will be explicitly deleted or stopped
using the low-level API.

Cases that are relying on links being automatically deleted
in cleanup() will potentially find that they are now no longer
deleted, but these cases should be rare.

mininet/link.py

@@ -197,9 +197,10 @@ def config( self, mac=None, ip=None, ifconfig=None,
     def delete( self ):
         "Delete interface"
         self.cmd( 'ip link del ' + self.name )
-        if self.node.inNamespace:
-            # Link may have been dumped into root NS
-            quietRun( 'ip link del ' + self.name )
+        # We used to do this, but it slows us down:
+        # if self.node.inNamespace:
+        # Link may have been dumped into root NS
+        # quietRun( 'ip link del ' + self.name )
 
     def status( self ):
         "Return intf status as a string"

mininet/node.py

@@ -194,10 +194,11 @@ def _popen( self, cmd, **params ):
 
     def cleanup( self ):
         "Help python collect its garbage."
+        # We used to do this, but it slows us down:
         # Intfs may end up in root NS
-        for intfName in self.intfNames():
-            if self.name in intfName:
-                quietRun( 'ip link del ' + intfName )
+        # for intfName in self.intfNames():
+        # if self.name in intfName:
+        # quietRun( 'ip link del ' + intfName )
         self.shell = None
 
     # Subshell I/O, commands and control
@@ -1311,10 +1312,6 @@ def stop( self, *args, **kwargs ):
         super( OVSBatch, self ).stop( *args, **kwargs )
         self.started = False
          
-    def cleanup( self):
-        "Don't bother to clean up"
-        return
-
 
 class IVSSwitch( Switch ):
     "Indigo Virtual Switch"