kill all proceses inside all dhcp-agent's net.namespaces,

that using ip protocol. When dhcp agent stops.

Change-Id: Ie84fdc70edaad3ab898bdb577f2dae2aeb9462d3
Closes-Bug: #1285929
kill all proceses inside all l3-agent's net.namespaces,

that using ip protocol. When l3 agent start/stop.
Also remove unneeded namespaces.

Change-Id: I7e5203f6cec646a8b70609f2bf3b785066068aeb
Closes-Bug: #1310926