Allow disable MOM KSM control.

This patch add ksmEnabled var to enable/disable mom ksm control.
Now users can use vdsClient to runtime disable/enable
(default enabled) ksm control:

 $ vdsClient -s 0 setMOMPolicyParameters ksmEnabled=False

Change-Id: Icc4333ce92561e23c062c398e24f876a74056a05
Bug-Url: http://bugzilla.redhat.com/1025780
Signed-off-by: Amador Pahim <apahim@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/20879
Reviewed-by: Martin Sivák <msivak@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>