Never replicate automerge-cache commits

Whenever a change is diffed in the UI, the merge result is stored
as a commit under the refs/automerge-cache namespace in the related
git.  These commits are then replicated, which is not necessary.

Add checks to prevent these commits from being replicated.

Change-Id: Ia1896a822a9901918d318d7641e2e8b63a0cf355

src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index 27a3901..afd7f91 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -426,7 +426,7 @@
     boolean noPerms = !pool.isReplicatePermissions();
     Map<String, Ref> remote = listRemote(tn);
     for (Ref src : local.values()) {
-      if (noPerms && GitRepositoryManager.REF_CONFIG.equals(src.getName())) {
+      if (!canPushRef(src.getName(), noPerms)) {
         continue;
       }
 
@@ -463,8 +463,7 @@
       if (spec != null) {
         // If the ref still exists locally, send it, otherwise delete it.
         Ref srcRef = local.get(src);
-        if (srcRef != null &&
-            !(noPerms && GitRepositoryManager.REF_CONFIG.equals(src))) {
+        if (srcRef != null && canPushRef(src, noPerms)) {
           push(cmds, spec, srcRef);
         } else if (config.isMirror()) {
           delete(cmds, spec);
@@ -474,6 +473,11 @@
     return cmds;
   }
 
+  private boolean canPushRef(String ref, boolean noPerms) {
+    return !(noPerms && GitRepositoryManager.REF_CONFIG.equals(ref)) &&
+        !ref.startsWith(GitRepositoryManager.REFS_CACHE_AUTOMERGE);
+  }
+
   private Map<String, Ref> listRemote(Transport tn)
       throws NotSupportedException, TransportException {
     FetchConnection fc = tn.openFetch();