engine: Add support for multiple IDs in unlock_entity.sh

Adds support to enter multiple IDs of same type as parameters of
unlock_entity.sh script. This patch make '-i' parameter obsolete
and entity IDs has to be entered as last parameter of the script.
Example:

  unlock_entity.sh -t vm 1 2 3

Change-Id: Ic1f9807eef92b9d4cf6f0c020e059ffe549badf2
Bug-Url: https://bugzilla.redhat.com/960448
Signed-off-by: Martin Perina <mperina@redhat.com>