jsonrpc: StoragePool_removeVM

Align naming between API.py and schema.

Change-Id: I16acb11982e70ff7f8a05ac816d36b2aa34caea0
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>
Reviewed-on: http://gerrit.ovirt.org/35548
Reviewed-by: Oved Ourfali <oourfali@redhat.com>
Reviewed-by: Adam Litke <alitke@redhat.com>