added vt uniq to remove duplicate variants, fixes https://github.com/bcbio/bcbio-nextgen/issues/2567#issuecomment-462940489 	modified:   gnomad_exome.yaml
added vt uniq to remove duplicate variants,
fixes https://github.com/bcbio/bcbio-nextgen/issues/2567#issuecomment-462940489
	modified:   gnomad_exome.yaml

chapmanb/cloudbiolinux,chapmanb/cloudbiolinux,chapmanb/cloudbiolinux,chapmanb/cloudbiolinux