fix broken test in datadriven/test_variants.py
fix broken test in datadriven/test_variants.py

ga4gh/server,macieksmuga/server,macieksmuga/server,ga4gh/server,ohsu-computational-biology/server,david4096/ga4gh-server,ga4gh/server,ohsu-computational-biology/server,dcolligan/server,david4096/ga4gh-server,dcolligan/server,macieksmuga/server,saupchurch/server,saupchurch/server,dcolligan/server,david4096/ga4gh-server,ohsu-computational-biology/server,saupchurch/server