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/linearbandwidth.py

@@ -27,7 +27,7 @@ of switches, this example demonstrates:
 from mininet.net import Mininet
 from mininet.node import UserSwitch, OVSKernelSwitch, Controller
 from mininet.topo import Topo
-from mininet.log import lg
+from mininet.log import lg, info
 from mininet.util import irange, quietRun
 from mininet.link import TCLink
 from functools import partial
@@ -84,7 +84,7 @@ def linearBandwidthTest( lengths ):
     assert 'reno' in output
 
     for datapath in switches.keys():
-        print( "*** testing", datapath, "datapath" )
+        info( "*** testing", datapath, "datapath\n" )
         Switch = switches[ datapath ]
         results[ datapath ] = []
         link = partial( TCLink, delay='1ms' )
@@ -92,36 +92,34 @@ def linearBandwidthTest( lengths ):
                        controller=Controller, waitConnected=True,
                        link=link )
         net.start()
-        print( "*** testing basic connectivity" )
+        info( "*** testing basic connectivity\n" )
         for n in lengths:
             net.ping( [ net.hosts[ 0 ], net.hosts[ n ] ] )
-        print( "*** testing bandwidth" )
+        info( "*** testing bandwidth\n" )
         for n in lengths:
             src, dst = net.hosts[ 0 ], net.hosts[ n ]
             # Try to prime the pump to reduce PACKET_INs during test
             # since the reference controller is reactive
             src.cmd( 'telnet', dst.IP(), '5001' )
-            print( "testing", src.name, "<->", dst.name )
+            info( "testing", src.name, "<->", dst.name, '\n' )
             bandwidth = net.iperf( [ src, dst ], seconds=10 )
-            print( bandwidth )
+            info( bandwidth, '\n' )
             flush()
             results[ datapath ] += [ ( n, bandwidth ) ]
         net.stop()
 
     for datapath in switches.keys():
-        print()
-        print( "*** Linear network results for", datapath, "datapath:" )
-        print()
+        info( "\n*** Linear network results for", datapath, "datapath:\n" )
         result = results[ datapath ]
-        print( "SwitchCount\tiperf Results" )
+        info( "SwitchCount\tiperf Results\n" )
         for switchCount, bandwidth in result:
-            print( switchCount, '\t\t' )
-            print( bandwidth[ 0 ], 'server, ', bandwidth[ 1 ], 'client' )
-        print()
-    print()
+            info( switchCount, '\t\t' )
+            info( bandwidth[ 0 ], 'server, ', bandwidth[ 1 ], 'client\n' )
+        info( '\n')
+    info( '\n' )
 
 if __name__ == '__main__':
     lg.setLogLevel( 'info' )
     sizes = [ 1, 10, 20, 40, 60, 80 ]
-    print( "*** Running linearBandwidthTest", sizes )
+    info( "*** Running linearBandwidthTest", sizes, '\n' )
     linearBandwidthTest( sizes  )