Factor setPatchSetId out of ChangeUpdate

I missed this when factoring out AbstractChangeUpdate from
ChangeUpdate.

Change-Id: If6eb57fa1a2ed9b37061bdca2fcde200ef034329
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/AbstractChangeUpdate.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/AbstractChangeUpdate.java
index aa1ff47..636f24c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/AbstractChangeUpdate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/AbstractChangeUpdate.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.notedb;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.GERRIT_PLACEHOLDER_HOST;
 
 import com.google.gerrit.reviewdb.client.Account;
@@ -70,6 +71,12 @@
     return (IdentifiedUser) ctl.getCurrentUser();
   }
 
+  public void setPatchSetId(PatchSet.Id psId) {
+    checkArgument(psId == null
+        || psId.getParentKey().equals(getChange().getId()));
+    this.psId = psId;
+  }
+
   private void load() throws IOException {
     if (migration.write() && getRevision() == null) {
       Repository repo = repoManager.openRepository(getProjectName());
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
index 7b9ef90..b1ae5ad 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
@@ -170,12 +170,6 @@
     this.subject = subject;
   }
 
-  public void setPatchSetId(PatchSet.Id psId) {
-    checkArgument(psId == null
-        || psId.getParentKey().equals(getChange().getId()));
-    this.psId = psId;
-  }
-
   public void setChangeMessage(String changeMessage) {
     this.changeMessage = changeMessage;
   }