bgp: move ssh configuration to bgp config file

You can't pass ssh.py to run command any more. If you need ssh CLI,
update the bgp config file and then:

ryu run —-config-file /path/to/ryu.conf /path/to/ryu/ryu/services/protocols/application.py

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>