Allow to continue reindex despite failures

Display a warning when a change is not found but then
continue to try to reindex the rest of the changes, consistently
with the current behavior of the command.

Change-Id: Idbd3d450c34788a9f5dd304b052e5810593088fe

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

@@ -44,7 +44,7 @@ final class IndexChangesCommand extends SshCommand {
     try {
       changeArgumentParser.addChange(token, changes, null, false);
     } catch (UnloggedFailure e) {
-      throw new IllegalArgumentException(e.getMessage(), e);
+      writeError("warning", e.getMessage());
     } catch (OrmException e) {
       throw new IllegalArgumentException("database is down", e);
     }