api: Remove some unneeded functions from vdsmapi.py

Change-Id: I25d534033f089bf9f36592bd2be0e98f2fde2dfe
Signed-off-by: Adam Litke <agl@us.ibm.com>
Reviewed-on: http://gerrit.ovirt.org/11865
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>