Fix typo

bin/mn

@@ -30,7 +30,7 @@ from mininet.node import ( Host, CPULimitedHost, Controller, OVSController,
                            UserSwitch, OVSSwitch, OVSBridge,
                            IVSSwitch )
 from mininet.nodelib import LinuxBridge, Server
-from mininet.link import Link, TCLink, TCULInk, OVSLink
+from mininet.link import Link, TCLink, TCULink, OVSLink
 from mininet.topo import ( SingleSwitchTopo, LinearTopo,
                            SingleSwitchReversedTopo, MinimalTopo )
 import mininet.topolib