engine : VdsUpdateRuntimeInfo updates the data of a specific VDS.

This change migrates all VM updates the VdsUpdateRuntimeInfo process does to
batch updates - improving performance.

Change-Id: Ie3e9735f4174ebabbe293d397d931aba72bbbd7b
Signed-off-by: lzelkha@redhat.com <liran.zelkha@gmail.com>