Revert "Revert "AU: do not copy filesystem during full updates""

This reverts commit d1cd325c3135d88498483da811b594ba6b91ce42

The problem that caused all autotests to fail with the original CL has now been rectified; lab devservers were updated to send the correct delta flag in their omaha response.

Change-Id: I664afb33f72856572baaa658cbd473c07271af36
Reviewed-on: https://gerrit.chromium.org/gerrit/56600
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>

utils.cc

diff --git a/utils.cc b/utils.cc
index be98a71..a6d8d91 100644
--- a/utils.cc
+++ b/utils.cc
@@ -848,8 +848,8 @@
       return "kErrorCodeFilesystemCopierError";
     case kErrorCodePostinstallRunnerError:
       return "kErrorCodePostinstallRunnerError";
-    case kErrorCodeSetBootableFlagError:
-      return "kErrorCodeSetBootableFlagError";
+    case kErrorCodePayloadMismatchedType:
+      return "kErrorCodePayloadMismatchedType";
     case kErrorCodeInstallDeviceOpenError:
       return "kErrorCodeInstallDeviceOpenError";
     case kErrorCodeKernelDeviceOpenError: