Rev gatk-public to 4.alpha.2-234-gc3a44c9-20170427.144324-1 (#1012)
Rev gatk-public to 4.alpha.2-234-gc3a44c9-20170427.144324-1 (#1012)

This snapshot includes a change to make it easier to use GenotypeGVCFs
with GenomicsDB input: JSON files no longer need to be explicitly
provided on the command line.
frank-y-liu/gatk,ksthesis/gatk,broadinstitute/hellbender,frank-y-liu/gatk,magicDGS/gatk,broadinstitute/hellbender,broadinstitute/hellbender,frank-y-liu/gatk,magicDGS/gatk,frank-y-liu/gatk,broadinstitute/hellbender,magicDGS/gatk,magicDGS/gatk,frank-y-liu/gatk,magicDGS/gatk,magicDGS/gatk,broadinstitute/hellbender,ksthesis/gatk,ksthesis/gatk,ksthesis/gatk,broadinstitute/hellbender,ksthesis/gatk,ksthesis/gatk,frank-y-liu/gatk