fixes test_kill_pids_in_file conflicts

Fixes Bug: #1231246
Change-Id: Ibedd59d6570cd8d5020e99125c6808d5d2170851
Call _destroy_metadata_proxy from _destroy_router_namespaces

Refactor _spawn/destroy_metadata_proxy so that it can be called
with only the namespace and the router_id.

Change-Id: Id1c33b22c7c3bd35c54a7c9ad419831bfed8746b
Closes-Bug: #1252856
Update Zhenguo Niu's mailmap

Using new email address.

Change-Id: I77190d0da0dbd4480ff03bcfe84540292cc81ea3
Merge "Call _destroy_metadata_proxy from _destroy_router_namespaces"
Merge "Update Zhenguo Niu's mailmap"
Merge "fixes test_kill_pids_in_file conflicts"