Correct ref name

The ref name was not following the name specs of JGit. Updated the name
to not include a trailing slash.

Change-Id: Ia6849dab4a291fdbbb9412179732e6fe8e763cb1
diff --git a/java/com/google/gerrit/plugins/checks/CheckerRef.java b/java/com/google/gerrit/plugins/checks/CheckerRef.java
index 2e7e263..6e2e246 100644
--- a/java/com/google/gerrit/plugins/checks/CheckerRef.java
+++ b/java/com/google/gerrit/plugins/checks/CheckerRef.java
@@ -24,7 +24,7 @@
   public static final String REFS_CHECKERS = "refs/checkers/";
 
   /** Ref that stores the repository to checkers map. */
-  public static final String REFS_META_CHECKERS = "refs/meta/checkers/";
+  public static final String REFS_META_CHECKERS = "refs/meta/checkers";
 
   /** Suffix for check refs. */
   public static final String CHECKS_SUFFIX = "/checks";