Fix memory leaks in NewIndex() and OpenIndex()
Fix memory leaks in NewIndex() and OpenIndex()

orivej/git2go,libgit2/git2go,libgit2/git2go,clns/git2go,orivej/git2go,pks-t/git2go,ezwiebel/git2go,pks-t/git2go,clns/git2go,ezwiebel/git2go,orivej/git2go,libgit2/git2go,clns/git2go,ezwiebel/git2go