No more Filtered Reads tag.

All synthetic reads are marked with the reduced read tag.

public/java/src/org/broadinstitute/sting/utils/sam/GATKSAMRecord.java

@@ -45,7 +45,6 @@ import java.util.Map;
  */
 public class GATKSAMRecord extends BAMRecord {
     public static final String REDUCED_READ_CONSENSUS_TAG = "RR";
-    public static final String REDUCED_READ_FILTERED_TAG = "RF";
 
     // the SAMRecord data we're caching
     private String mReadString = null;