add unit test for ubuntu_net_manager
add unit test for ubuntu_net_manager

uzzz/bosh-agent,cloudfoundry/bosh-agent,gu-bin/bosh-agent,mattcui/bosh-agent,gu-bin/bosh-agent,uzzz/bosh-agent,cloudfoundry/bosh-agent,gu-bin/bosh-agent,mattcui/bosh-agent,uzzz/bosh-agent,mattcui/bosh-agent