Favor checkID over check_id.

Per golint:

  canaryd.go:55:23: don't use underscores in Go names; func parameter check_id should be checkID
  canaryd.go:64:18: don't use underscores in Go names; func parameter check_id should be checkID
  canaryd.go:68:29: don't use underscores in Go names; func parameter check_id should be checkID
  canaryd.go:75:26: don't use underscores in Go names; func parameter check_id should be checkID
  canaryd.go:107:2: don't use underscores in Go names; var check_id should be checkID
Favor rS over r_s.

Per golint:

  canaryd.go:108:2: don't use underscores in Go names; var r_s should be rS
Eliminate unnecessary if-else block.

Per golint:

  canaryd.go:100:9: if block ends with a return statement, so drop this else and outdent its block
Adjust various struct field names and their respective calls.

Per golint:

  canaryd.go:26:2: struct field Id should be ID
  canaryd.go:27:2: struct field Url should be URL
  canaryd.go:32:2: struct field Id should be ID
  canaryd.go:36:2: struct field HttpStatus should be HTTPStatus
  canaryd.go:37:2: struct field LocalIp should be LocalIP
  canaryd.go:38:2: struct field PrimaryIp should be PrimaryIP
merge anachronistic-lint