python: Fix print function compatibility.

The print statement from Python 2 is a function in Python 3.  Enable
print function support for Python 2 and convert print statements to
function calls.

Enable the H233 flake8 warning.  If the hacking plugin is installed,
this will generate warnings for print statement usage not compatible
with Python 3.

  H233 Python 3.x incompatible use of print operator

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>

tests/test-reconnect.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
+
 import errno
 import sys
 
@@ -74,11 +76,11 @@ def do_run(arg):
     if action is None:
         pass
     elif action == ovs.reconnect.CONNECT:
-        print "  should connect"
+        print("  should connect")
     elif action == ovs.reconnect.DISCONNECT:
-        print "  should disconnect"
+        print("  should disconnect")
     elif action == ovs.reconnect.PROBE:
-        print "  should send probe"
+        print("  should send probe")
     else:
         assert False
 
@@ -92,10 +94,10 @@ def do_timeout(_):
     global now
     timeout = r.timeout(now)
     if timeout >= 0:
-        print "  advance %d ms" % timeout
+        print("  advance %d ms" % timeout)
         now += timeout
     else:
-        print "  no timeout"
+        print("  no timeout")
 
 
 def do_set_max_tries(arg):
@@ -183,7 +185,7 @@ def main():
     r = ovs.reconnect.Reconnect(now)
     r.set_name("remote")
     prev = r.get_stats(now)
-    print "### t=%d ###" % now
+    print("### t=%d ###" % now)
     old_time = now
     old_max_tries = r.get_max_tries()
     while True:
@@ -191,7 +193,7 @@ def main():
         if line == "":
             break
 
-        print line[:-1]
+        print(line[:-1])
         if line[0] == "#":
             continue
 
@@ -207,15 +209,15 @@ def main():
         commands[command](op)
 
         if old_time != now:
-            print
-            print "### t=%d ###" % now
+            print()
+            print("### t=%d ###" % now)
 
         cur = r.get_stats(now)
         diff_stats(prev, cur, now - old_time)
         prev = cur
         if r.get_max_tries() != old_max_tries:
             old_max_tries = r.get_max_tries()
-            print "  %d tries left" % old_max_tries
+            print("  %d tries left" % old_max_tries)
 
         old_time = now