When parsing info/refs, no checks were applied that the file was in
the requried format. Since the file is read from a remote webserver,
this isn't guarenteed to be true. Add a check that the file at least
only contains lines that consist of 40 characters followed by a tab
and then the ref name.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>