Fix ovs-vsctl executed in worlddump.py failed issue
Fix ovs-vsctl executed in worlddump.py failed issue

add sudo before ovs-vsctl command.

Change-Id: I1a7dd9504da766beb452bd749e325931678de64e
Closes-Bug: #1576560

noironetworks/devstack,richliu/devstack,group-policy/devstack,bigswitch/devstack,nawawi/openstack,dtroyer/devstack,openstack-dev/devstack,group-policy/devstack,nawawi/openstack,richliu/devstack,bswartz/devstack,dtroyer/devstack,Mahito/devstack,bswartz/devstack,Mahito/devstack,openstack-dev/devstack,bigswitch/devstack,noironetworks/devstack