Fix leak from ks_init in tabix_file_iterator.
Fix leak from ks_init in tabix_file_iterator.

daler/pysam,TyberiusPrime/pysam,bioinformed/pysam,dannon/pysam,daler/pysam,kyleabeauchamp/pysam,daler/pysam,nlhepler/pysam,bioinformed/pysam,carolinux/pysam,mattions/pysam,kyleabeauchamp/pysam,bioinformed/pysam,mattions/pysam,nlhepler/pysam,kyleabeauchamp/pysam,brendanofallon/pysam,carolinux/pysam,TyberiusPrime/pysam,brendanofallon/pysam,pysam-developers/pysam,nlhepler/pysam,mattions/pysam,brendanofallon/pysam,dannon/pysam,dannon/pysam,carolinux/pysam,nlhepler/pysam,daler/pysam,brendanofallon/pysam,mattions/pysam,daler/pysam,nlhepler/pysam,bioinformed/pysam,kyleabeauchamp/pysam,brendanofallon/pysam,dannon/pysam,mattions/pysam,TyberiusPrime/pysam,carolinux/pysam,kyleabeauchamp/pysam,dannon/pysam,bioinformed/pysam,TyberiusPrime/pysam,pysam-developers/pysam,pysam-developers/pysam,pysam-developers/pysam,carolinux/pysam,TyberiusPrime/pysam