Unconditionally register key handler

For reasons not entirely understood, we can
have an ipmi command object without registering
a key handler.  Unconditionally register the key handler
on each use of the command object.  This still saves the
network load of logging in, so it's not a terrible workaround.

confluent_server/confluent/plugins/hardwaremanagement/ipmi.py

@@ -345,6 +345,7 @@ class IpmiHandler(object):
                 if ge[0] == -2:
                     raise exc.TargetEndpointUnreachable(ge[1])
         self.ipmicmd = persistent_ipmicmds[(node, tenant)]
+        self.ipmicmd.setup_confluent_keyhandler()
 
     bootdevices = {
         'optical': 'cd'
@@ -356,7 +357,6 @@ class IpmiHandler(object):
             self.error = response['error']
         else:
             self.loggedin = True
-            ipmicmd.setup_confluent_keyhandler()
         self._logevt.set()
 
     def handle_request(self):