Update default value for agent_required attribute

Update default value for agent_required under the
section [ml2_sriov] to be aligned with default config value.

Change-Id: I5903dedb2b8dc6bbda7c921ef747ffae358b3c05
Closes-Bug: 1386660
Fix missing allowed command in openvswitch xenapi agent

Add allowed command "ovsdb-client" to ALLOWED_CMDS list.

Change-Id: I274604229f90ba00722b1001cbc7404cd3e8070d
Closes-Bug: #1338447
Merge "Update default value for agent_required attribute"
Merge "Fix missing allowed command in openvswitch xenapi agent"