Add name of the enum to message to help looking up.

chromeos/cryptohome/homedir_methods.cc

Index: chromeos/cryptohome/homedir_methods.cc
diff --git a/chromeos/cryptohome/homedir_methods.cc b/chromeos/cryptohome/homedir_methods.cc
index 53603a151d0b67b8733cf6a84e605247ea3687dc..e4ba875512628e8f3260563ca7efa6cfb8cb3291 100644
--- a/chromeos/cryptohome/homedir_methods.cc
+++ b/chromeos/cryptohome/homedir_methods.cc
@@ -411,7 +411,9 @@ class HomedirMethodsImpl : public HomedirMethods {
     }
     if (reply.has_error()) {
       if (reply.error() != CRYPTOHOME_ERROR_NOT_SET) {
-        LOGIN_LOG(ERROR) << "HomedirMethods MountEx error: " << reply.error();
+        LOGIN_LOG(ERROR)
+            << "HomedirMethods MountEx error (CryptohomeErrorCode): "
+            << reply.error();
         callback.Run(false, MapError(reply.error()), std::string());
         return;
       }