Description of problem:
typo in "vmSetBalloonTarget", the error:

2015-07-06 13:46:35,643 - mom.Controllers.Balloon - INFO - Ballooning guest:mom-1 from 2097152 to 1992294
2015-07-06 13:46:35,694 - mom.PolicyEngine - ERROR - Policy Engine crashed
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/mom/PolicyEngine.py", line 131, in run
    self.do_controls()
  File "/usr/lib/python2.7/site-packages/mom/PolicyEngine.py", line 122, in do_controls
    c.process(host, guest_list)
  File "/usr/lib/python2.7/site-packages/mom/Controllers/Balloon.py", line 42, in process
    self.process_guest(guest)
  File "/usr/lib/python2.7/site-packages/mom/Controllers/Balloon.py", line 38, in process_guest
    self.hypervisor_iface.setVmBalloonTarget(uuid, target)
  File "/usr/lib/python2.7/site-packages/mom/HypervisorInterfaces/vdsmxmlrpcInterface.py", line 144, in setVmBalloonTarget
    response = self.vdsm_api.vmSetBalloonTarget(uuid, target)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1224, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1578, in __request
    verbose=self.__verbose
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1264, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1297, in single_request
    return self.parse_response(response)
  File "/usr/lib/python2.7/site-packages/vdsm/vdscli.py", line 43, in wrapped_parse_response
    return old_parse_response(*args, **kwargs)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1473, in parse_response
    return u.close()
  File "/usr/lib64/python2.7/xmlrpclib.py", line 793, in close
    raise Fault(**self._stack[0])
Fault: <Fault 1: '<type \'exceptions.Exception\'>:method "vmSetBalloonTarget" is not supported'>
2015-07-06 13:46:45,558 - mom.RPCServer - INFO - ping()

Version-Release number of selected component (if applicable):
3.6.3 - engine 

How reproducible:
100%

Steps to Reproduce:
0. make sure the overcommit is disabeld
   - go to Clusters
   - right click on the cluster -> edit
   - go to Optimization tab 
   - make sure this radio button is chosen: None - Disable memory overcommit

1.enable ballooning on the cluster : 
  - go to Clusters
  - right click on the cluster -> edit 
  - go to Optimization tab
  - enable the checkbox : Enable Memory Balloon Optimization

2.Sync mom policy 
  - go to Clusters
  - choose your cluster
  - on the cluster sub tab choose your hosts and click on 'Sync MoM policy'

3.Create VM with OS installed (512MB guaranteed memory / 2GB full memory) 

4. optionall - on the host, change in the file  "/etc/vdsm/mom.d/02-balloon.policy" from defvar pressure_threshold 0.20 to defvar pressure_threshold 0.40 - to make ballooning Run faster 

5. Run memory load on host

6.  look the the mom log 

Actual results:
Fault: <Fault 1: '<type \'exceptions.Exception\'>:method "vmSetBalloonTarget" is not supported'>

Expected results:
the ballooning should work

Additional info: