phosphor-debug-collector: enhance multihost support

- Change the dbus object path to faultlog/0 and faultlog/1 to align
  current gbmcewb LogService/faultLog URL logic.

Tested:
```
 busctl tree xyz.openbmc_project.Dump.Manager
└─ /xyz
  └─ /xyz/openbmc_project
    └─ /xyz/openbmc_project/dump
      ├─ /xyz/openbmc_project/dump/bmc
      └─ /xyz/openbmc_project/dump/faultlog
        ├─ /xyz/openbmc_project/dump/faultlog/0
        └─ /xyz/openbmc_project/dump/faultlog/1
```

Fusion-Link:
platform5: fusion2.corp.google.com/cc347b63-44dc-3f2e-b86a-773e009370bd
platform11: fusion2.corp.google.com/6cc6a249-4e06-3307-95b4-b1ec1ddc42c9
platform15: http://fusion2.corp.google.com/a7a5078a-b62e-3903-9ea9-8488ddfd0bf4
platform17: fusion2.corp.google.com/31945851-7314-3b61-884e-ee282d4fa7e5
Google-Bug-Id: 469625654
Change-Id: Ibf28270eae13eaf51f0d471cdb8263979c8e3975
Signed-off-by: Jimmy Chang <cmchang@google.com>