BackupRef: Add missing cases in switch on RefUpdate.Result

Change-Id: I2ec62ca35305c6fd69cac4c8dbfb4f4d701af86f

src/main/java/com/googlesource/gerrit/plugins/refprotection/BackupRef.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/refprotection/BackupRef.java b/src/main/java/com/googlesource/gerrit/plugins/refprotection/BackupRef.java
index 8119b16..30eaeca 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/refprotection/BackupRef.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/refprotection/BackupRef.java
@@ -149,6 +149,8 @@
             case NO_CHANGE:
             case REJECTED_CURRENT_BRANCH:
             case RENAMED:
+            case REJECTED_MISSING_OBJECT:
+            case REJECTED_OTHER_REASON:
             default:
               log.error("Unexpected result while creating backup tag: {}", result);
           }