ovirt-node-features: Do not document daemon mode

Previously the -d switch was mentioned, but we do not want to support
this, as it is pulling in bootle (pythonlib).
To address this we are removing the documentation and make it an
unsupported feature.

Change-Id: I161c2888633d8f02a492a52d050c767d1a995ff7
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1120565
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>