Fix attribute error on particularly bad connections

When simulating 80% packet loss, it was discovered that a console
being close() due to inability to complete session establishment
will not have keepaliveid registered yet.

Change-Id: I839645b13cbe30ae71e104c44e63896a4802befe

pyghmi/ipmi/console.py

@@ -42,6 +42,7 @@ class Console(object):
     def __init__(self, bmc, userid, password,
                  iohandler, port=623,
                  force=False, kg=None):
+        self.keepaliveid = None
         self.connected = False
         self.broken = False
         self.out_handler = iohandler