Fix support for Python 2.6, 3.0, 3.1.

diff --git a/src/paho/mqtt/client.py b/src/paho/mqtt/client.py
index 9001bb56ca7ba8d0ca4d933d1b3ea6974f8769c5..1ba6f9b9659aec3c2db43617361e10c1a9775ffd 100755 (executable)
--- a/src/paho/mqtt/client.py
+++ b/src/paho/mqtt/client.py
@@ -559,6 +559,9 @@ class Client:
             raise ValueError('Invalid port number.')
         if keepalive < 0:
             raise ValueError('Keepalive must be >=0.')
+        if bind_address != "" and bind_address != None:
+            if (sys.version_info[0] == 2 and sys.version_info[1] < 7) or (sys.version_info[0] == 3 and sys.version_info[1] < 2):
+                raise ValueError('bind_address requires Python 2.7 or 3.2.')
 
         self._host = host
         self._port = port
@@ -607,7 +610,10 @@ class Client:
         self._messages_reconnect_reset()
 
         try:
-            self._sock = socket.create_connection((self._host, self._port), source_address=(self._bind_address, 0))
+            if (sys.version_info[0] == 2 and sys.version_info[1] < 7) or (sys.version_info[0] == 3 and sys.version_info[1] < 2):
+                self._sock = socket.create_connection((self._host, self._port), source_address=(self._bind_address, 0))
+            else:
+                self._sock = socket.create_connection((self._host, self._port))
         except socket.error as err:
             (msg) = err
             if msg.errno != errno.EINPROGRESS: