Merge pull request #606 from oliviertilmans/patch-2

link: Fix circular import

mininet/link.py

@@ -26,7 +26,6 @@ Link: basic link class for creating veth pairs
 
 from mininet.log import info, error, debug
 from mininet.util import makeIntfPair
-import mininet.node
 import re
 
 class Intf( object ):
@@ -531,10 +530,12 @@ class OVSLink( Link ):
        than ~64 OVS patch links should be used in row."""
 
     def __init__( self, node1, node2, **kwargs ):
+        from mininet.node import OVSSwitch
+
         "See Link.__init__() for options"
         self.isPatchLink = False
-        if ( isinstance( node1, mininet.node.OVSSwitch ) and
-             isinstance( node2, mininet.node.OVSSwitch ) ):
+        if ( isinstance( node1, OVSSwitch ) and
+             isinstance( node2, OVSSwitch ) ):
             self.isPatchLink = True
             kwargs.update( cls1=OVSIntf, cls2=OVSIntf )
         Link.__init__( self, node1, node2, **kwargs )