Ignore refs/multi-site/version on global-refdb in push replication filter

When I509dd7075b0 stopped updating the SHA1 for refs/multi-site/version
in global-refdb in this stable-3.4 branch, it did not take into
consideration that existing setups may have plenty of
refs/multi-site/version already stored on them.

Stopping the update of those refs on the global-refdb had a negative
impact on the consistency of the replication of refs/multi-site/version
across the multi-site clusters, causing missed replication events.

Consider the refs/multi-site/version on global-refdb as non-existent
and skip altogether the associated checks if the associated local refs
were already up-to-date.
This change effectively ignores weather the local refs/multi-site/version
is up-to-date or not and always pushes the refs to replication remotes.

This is the completion of the similar fix performed on the
MultisiteReplicationFetchFilter in I8b938675.

Change-Id: I833138849807475a7aed308d8703bb7e16728d2d

src/main/java/com/googlesource/gerrit/plugins/multisite/validation/MultisiteReplicationPushFilter.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/MultisiteReplicationPushFilter.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/MultisiteReplicationPushFilter.java
index 6f9c2e7..777886d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/MultisiteReplicationPushFilter.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/MultisiteReplicationPushFilter.java
@@ -14,6 +14,8 @@
 
 package com.googlesource.gerrit.plugins.multisite.validation;
 
+import static com.googlesource.gerrit.plugins.multisite.validation.ProjectVersionRefUpdate.MULTI_SITE_VERSIONING_REF;
+
 import com.gerritforge.gerrit.globalrefdb.GlobalRefDbLockException;
 import com.gerritforge.gerrit.globalrefdb.validation.SharedRefDatabaseWrapper;
 import com.google.common.base.Preconditions;
@@ -111,6 +113,10 @@
 
   private Optional<RemoteRefUpdate> isUpToDateWithRetry(
       String projectName, Repository repository, RemoteRefUpdate refUpdate) {
+    if (shouldNotBeTrackedAnymoreOnGlobalRefDb(refUpdate.getSrcRef())) {
+      return Optional.of(refUpdate);
+    }
+
     String ref = refUpdate.getSrcRef();
     try {
       if (sharedRefDb.isUpToDate(
@@ -146,6 +152,19 @@
     }
   }
 
+  /*
+   * Since ac43a5f94c773c9db7a73d44035961d69d13fa53 the 'refs/multi-site/version' is
+   * not updated anymore on the global-refdb; however, the values stored already
+   * on the global-refdb could get in the way and prevent replication from happening
+   * as expected.
+   *
+   * Exclude the 'refs/multi-site/version' from local vs. global refdb checking
+   * pretending that the global-refdb for that ref did not exist.
+   */
+  private boolean shouldNotBeTrackedAnymoreOnGlobalRefDb(String ref) {
+    return MULTI_SITE_VERSIONING_REF.equals(ref);
+  }
+
   private RemoteRefUpdate newRemoteRefUpdateWithObjectId(
       Repository localDb, RemoteRefUpdate refUpdate, ObjectId reloadedNewObjectId)
       throws IOException {