Change the format of remote host goldfish instance names

The prefix "host-<ip_addr>-goldfish" is changed to
"host-goldfish-<ip_addr>". The new format can be distinguished from
the cuttlefish prefix "host-<ip_addr>".

Test: acloud-dev delete -vv --instance-names \
      host-goldfish-192.168.9.3-5554-7476030-sdk_x86_64-sdk \
      --host-user root \
      --host-ssh-private-key-path ~/id_rsa \
      --rpeort-file ./report.json
Bug: 198254814
Change-Id: I52de64a3a988b8a96d2f12ce9127e575ce1814db
5 files changed