private boolean filterRowKey(Cell current) throws IOException {
    return filter != null && filter.filterRowKey(current);
  }
This function is to maintain backward compatibility for 0.94 filters. HBASE-6429 combines both
filterRow & filterRow({@code List<KeyValue> kvs}) functions. While 0.94 code or older, it may
not implement hasFilterRow as HBase-6429 expects because 0.94 hasFilterRow() only returns true
when filterRow({@code List<KeyValue> kvs}) is overridden not the filterRow(). Therefore, the
filterRow() will be skipped.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionScannerImpl.java