Improve log of FrE check

We would like to get in logs a string description of value received from
the server rather than the integer value associated with enum.

BUG=chromium:1021892
TEST=None

Change-Id: Ic1a97924b9b070f35e9e0854dc97380dd115d6c9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2142268Reviewed-by: Igor <igorcov@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Igor <igorcov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757747}

chrome/browser/chromeos/policy/auto_enrollment_client_impl.cc

@@ -267,7 +267,7 @@ class StateDownloadMessageProcessorFRE
     parsed_response.is_license_packaged_with_device.reset();
 
     // Logging as "WARNING" to make sure it's preserved in the logs.
-    LOG(WARNING) << "Received restore_mode=" << state_response.restore_mode();
+    LOG(WARNING) << "Received restore_mode=" << parsed_response.restore_mode;
 
     return parsed_response;
   }