Submit: use equals instead of != on Account.Ids

This was resulting in some SUBM records getting overwritten with
slightly-newer records in some cases.

Change-Id: I048a54acbb2f406d699cf5d6c92c872acda95930

gerrit-server/src/main/java/com/google/gerrit/server/change/Submit.java

@@ -419,7 +419,8 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
     }
 
     PatchSetApproval submit = ApprovalsUtil.getSubmitter(psId, byKey.values());
-    if (submit == null || submit.getAccountId() != caller.getAccountId()) {
+    if (submit == null
+        || !submit.getAccountId().equals(caller.getAccountId())) {
       submit = new PatchSetApproval(
           new PatchSetApproval.Key(
               rsrc.getPatchSet().getId(),