Extra PUT requests are sent

[Anurag Mishra]

If upload object operation is performed, when swift-object-server was killed , the 'HEAD' request from swift-proxy-server fails. After the first HEAD request failure swift-proxy-server retries 5 more times and it return HTTP response code '503 Service Unavailable‘ each time. Even after the failure of the first 'HEAD' request to the 'swift-object-server' the subsequent 'PUT' request to the 'swift-object-server' is retried 5 more times.
Similarly during update account when the swift-account-server is not active, so the POST request should not be sent after HEAD request, as when the HEAD request has already returned Response code : 503 twice, so this behaviour can be improved.