[vrouter] Install contrail-version « script » (close: #72)

Refs: http://lists.opencontrail.org/pipermail/dev_lists.opencontrail.org/2014-April/001024.html
  * https://github.com/Juniper/contrail-installer/blob/master/contrail.sh#L354-L364
  * https://github.com/Juniper/contrail-controller/blob/master/src/analytics/ruleparser/contrail-dbutils#L333
  * https://github.com/Juniper/contrail-controller/blob/master/src/base/misc_utils.cc#L100-L114
  * https://github.com/Juniper/contrail-controller/blob/master/src/config/common/vnc_cpu_info.py#L90-L102