fix(dreg): Remove grep "_" -v

Think this is breaking the analysis
Danko-Lab/proseq2.0#3
Danko-Lab/proseq2.0#4
cmuyehara/proseq2.0@b4349ba

modules/local/dreg_prep/templates/proseq2.0

@@ -70,7 +70,7 @@ readCount=`zcat ${prefix}.bed.gz | wc -l`
 echo \${readCount}
 
 ## Remove rRNA and reverse the strand (PRO-seq).
-zcat ${prefix}.bed.gz | grep "rRNA\\|chrM" -v | grep "_" -v | sort -k 1,1 -k2,2n - | gzip >${prefix}.nr.rs.bed.gz
+zcat ${prefix}.bed.gz | grep "rRNA\\|chrM" -v | sort -k 1,1 -k2,2n - | gzip >${prefix}.nr.rs.bed.gz
 echo 'Number of mappable reads (excluding rRNA):'
 echo `zcat ${prefix}.nr.rs.bed.gz | wc -l`