storage: filesystem, close shallow file when read
storage: filesystem, close shallow file when read

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

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