print -> info; end the horror of print vs. print()

Although we could use print() from __future__, this messes
up scripts which use examples as modules.

The simple, if not nicest for 2.7, solution is to use
info(), output() and other mininet.log functions. The disadvantage
is that we may have to adjust things if we change info() to
add automatic newlines, but we can burn that bridge in Mininet
3.x.

examples/mobility.py

@@ -23,7 +23,7 @@ to-do:
 from mininet.net import Mininet
 from mininet.node import OVSSwitch
 from mininet.topo import LinearTopo
-from mininet.log import output, warn
+from mininet.log import info, output, warn, setLogLevel
 
 from random import randint
 
@@ -106,30 +106,31 @@ def moveHost( host, oldSwitch, newSwitch, newPort=None ):
 
 def mobilityTest():
     "A simple test of mobility"
-    print( '* Simple mobility test' )
+    info( '* Simple mobility test\n' )
     net = Mininet( topo=LinearTopo( 3 ), switch=MobilitySwitch )
-    print( '* Starting network:' )
+    info( '* Starting network:\n' )
     net.start()
     printConnections( net.switches )
-    print( '* Testing network' )
+    info( '* Testing network\n' )
     net.pingAll()
-    print( '* Identifying switch interface for h1' )
+    info( '* Identifying switch interface for h1\n' )
     h1, old = net.get( 'h1', 's1' )
     for s in 2, 3, 1:
         new = net[ 's%d' % s ]
         port = randint( 10, 20 )
-        print( '* Moving', h1, 'from', old, 'to', new, 'port', port )
+        info( '* Moving', h1, 'from', old, 'to', new, 'port', port, '\n' )
         hintf, sintf = moveHost( h1, old, new, newPort=port )
-        print( '*', hintf, 'is now connected to', sintf )
-        print( '* Clearing out old flows' )
+        info( '*', hintf, 'is now connected to', sintf, '\n' )
+        info( '* Clearing out old flows\n' )
         for sw in net.switches:
             sw.dpctl( 'del-flows' )
-        print( '* New network:' )
+        info( '* New network:\n' )
         printConnections( net.switches )
-        print( '* Testing connectivity:' )
+        info( '* Testing connectivity:\n' )
         net.pingAll()
         old = new
     net.stop()
 
 if __name__ == '__main__':
+    setLogLevel( 'info' )
     mobilityTest()