fixed segfault when clearing tabix
fixed segfault when clearing tabix

hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS