repository: fix test for new Storage constructor
repository: fix test for new Storage constructor

Signed-off-by: Máximo Cuadros <6de7239924fbb83efa9bb5c97eb48a1df882d187@gmail.com>

src-d/go-git,mcuadros/go-git,src-d/go-git,go-git/go-git,mcuadros/go-git,go-git/go-git