Don't swallow lock failures

Re-throw lock failures after setting status to reflect them. Otherwise
it is difficult to track down their cause in logs.

Change-Id: Ib49a42391fd615474eb61558f6399d0f98e1ec59
diff --git a/java/com/googlesource/gerrit/plugins/supermanifest/SuperManifestRefUpdatedListener.java b/java/com/googlesource/gerrit/plugins/supermanifest/SuperManifestRefUpdatedListener.java
index 71a4ae9..ff2e08d 100644
--- a/java/com/googlesource/gerrit/plugins/supermanifest/SuperManifestRefUpdatedListener.java
+++ b/java/com/googlesource/gerrit/plugins/supermanifest/SuperManifestRefUpdatedListener.java
@@ -363,6 +363,7 @@
       status = "OK";
     } catch (ConcurrentRefUpdateException e) {
       status = "LOCK_FAILURE";
+      throw e;
     } finally {
       manifestUpdateResultCounter.increment(status);
     }