Sync with CrOS error codes.

Add to ErrorCode and metrics::DownloadErrorCode:

- kInternalLibCurlError
- kUnresolvedHostError
- kUnresolvedHostRecovered

Test: builds
Change-Id: Ibe11c02137860aed583b00b7e05b089ef84edb03
diff --git a/payload_state.cc b/payload_state.cc
index a6c3620..355552e 100644
--- a/payload_state.cc
+++ b/payload_state.cc
@@ -365,6 +365,9 @@
     case ErrorCode::kNoUpdate:
     case ErrorCode::kRollbackNotPossible:
     case ErrorCode::kFirstActiveOmahaPingSentPersistenceError:
+    case ErrorCode::kInternalLibCurlError:
+    case ErrorCode::kUnresolvedHostError:
+    case ErrorCode::kUnresolvedHostRecovered:
       LOG(INFO) << "Not incrementing URL index or failure count for this error";
       break;