Ensure success value returned from setRegion on tabix file when called with separate contig/start/end
vcfcreatemulti: Avoid segfault when passed VCF file with no variants
Revert "Ensure success value returned from setRegion on tabix file when called with separate contig/start/end"

This reverts commit 93866286a5dad9a9c0f02b105bcfbc8a06af58fe.
Merge pull request #29 from chapmanb/createmulti-empty

vcfcreatemulti: Avoid segfault when passed VCF file with no variants