vcfcreatemulti: Avoid segfault when passed VCF file with no variants
vcfcreatemulti: Avoid segfault when passed VCF file with no variants

ekg/vcflib,tomdcsmith/vcflib,zhmz90/vcflib,harshinamdar/vcflib,zhmz90/vcflib,travc/vcflib,zhmz90/vcflib,glennhickey/vcflib,wzugang/vcflib,zhmz90/vcflib,vcflib/vcflib,vcflib/vcflib,glennhickey/vcflib,wzugang/vcflib,tomdcsmith/vcflib,ekg/vcflib,vcflib/vcflib,wzugang/vcflib,vcflib/vcflib,glennhickey/vcflib,vcflib/vcflib,harshinamdar/vcflib,wzugang/vcflib,glennhickey/vcflib,ekg/vcflib,ekg/vcflib,ashishjain1988/vcflib,harshinamdar/vcflib,glennhickey/vcflib,wzugang/vcflib,ashishjain1988/vcflib,vcflib/vcflib,wzugang/vcflib,ashishjain1988/vcflib,harshinamdar/vcflib,tomdcsmith/vcflib,zhmz90/vcflib,vcflib/vcflib,zhmz90/vcflib,travc/vcflib,glennhickey/vcflib,ashishjain1988/vcflib,travc/vcflib,ekg/vcflib,ashishjain1988/vcflib,harshinamdar/vcflib,ashishjain1988/vcflib,harshinamdar/vcflib,vcflib/vcflib