Fix failure in test_agent_init. Initialize the vhost and xen_ll interface prefix during AgentParam::Init
Merge pull request #465 from Juniper/ashoksr_ut

Fix failure in test_agent_init. Initialize the vhost and xen_ll interfac...
Reset flow teardown_time on delete of flow_entry after its value is exported, so that it points to right value in case of flow entr reuse.
Merge remote branch 'github/master' into ashoksr_bugs