[#1083] objsvc/v2: Properly check response status after forwarding
Previously we had cryptic error:
```
debug get/remote.go:38 remote call failed {"component": "Object.Get service", "request": "HEAD", "address": "9sTxoVrhJ7WBtXQfK2NJ7zDV5yCF7BPLKK1XTxYPdGsP/BbHV4KZZ8y2BPqAT5kyjdHRLkfbtY2xf5uYoMVqxACn1", "raw": false, "local": false, "with session": false, "with bearer": false, "error": "unexpected header type <nil>"}
```
Now we have and expected error:
```
debug get/remote.go:38 remote call failed {"component": "Object.Get service", "request": "HEAD", "address": "D2rqaMG4D2VHdv3HKky8UYSYmwQFH2v9oXXqtyRZPTMy/BbHV4KZZ8y2BPqAT5kyjdHRLkfbtY2xf5uYoMVqxACn1", "raw": false, "local": false, "with session": false, "with bearer": false, "error": "status: code = 2049 message = object not found"}
```
Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>