fix: return connected address in RPC get_peers

[keroro520]

The RPC get_peers miss the peer connected address. Hence it may be empty addresses returned for inbound peers. e.g.

      {
         "addresses" : [],
         "version" : "0.29.0 (a6733e6 2020-02-26)",
         "node_id" : "QmPoPDhGPbNfAuDM1kmQFyY8cocC2SXipi6gYV6BmAj2w7",
         "is_outbound" : false
      }

This PR:

• Includes connected address in the returning addresses
• Uses the score recorded in peer_store as the returning peer score

[doitian]

Is it possible to add test cases to cover more branches instead of just relying on the RPC documentation test?

[keroro520]

Is it possible to add test cases to cover more branches instead of just relying on the RPC documentation test?

Adding integration tests can cover more detail. It seems hard to do it in unit tests.

[quake]

bors r=quake,doitian

[bors]

Build succeeded:

• continuous-integration/travis-ci/push