Cleaned up logic when discarding short pairs
Cleaned up logic when discarding short pairs

jas14/khmer,kdmurray91/khmer,Winterflower/khmer,F1000Research/khmer,F1000Research/khmer,jas14/khmer,ged-lab/khmer,F1000Research/khmer,Winterflower/khmer,kdmurray91/khmer,ged-lab/khmer,kdmurray91/khmer,jas14/khmer,Winterflower/khmer,souravsingh/khmer,souravsingh/khmer,souravsingh/khmer,ged-lab/khmer