ChangeIndexer: Disable auto-rebuilding changes

When a DFS ref update of a NoteDb meta ref fails due to a transient
error in the storage backend, we don't want to incur an additional
write to the ref during reindexing, as it may just fail again. Worse,
while BatchUpdate knows to ignore NoteDb write updates when executing
its NoteDbUpdateManager, it can't as easily ignore them while getting
its index futures. Thus an error that was successfully ignored is
likely to be followed by one that can't be.

Work around this for the case of NoteDb writes enabled but reads
disabled, by explicitly turning off auto-rebuilding from
ChangeIndexer. This doesn't help us in the case of NoteDb reads being
enabled, where we have to be able to read the latest NoteDb data from
the ref in order to reindex.

Change-Id: I64000a57ffcf73a9cbef42a6130e1fb4bc8e98f0

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/IndexChangesCommand.java

@@ -58,7 +58,7 @@ final class IndexChangesCommand extends SshCommand {
     for (ChangeResource rsrc : changes.values()) {
       try {
         index.apply(rsrc, new Index.Input());
-      } catch (IOException | RestApiException e) {
+      } catch (IOException | RestApiException | OrmException e) {
         ok = false;
         writeError("error", String.format(
             "failed to index change %s: %s", rsrc.getId(), e.getMessage()));