fix two remaining 'high impact outstanding' issues as found by coverity
fix two remaining 'high impact outstanding' issues as found by coverity

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