git-svn: remove redundant slashes from show-ignore

git-svn: remove redundant slashes from show-ignore

Jonathan Scott Duff wrote:

> Recently I tried "git svn showignore" on my parrot repository and it
> failed.  I tracked it down to the prop_walk() sub.  When it recurses,
> $path has an extra / on the beginning (i.e., when it recurses, it
> tries to get the props for "//apps" instead of "/apps").   I *think*
> this is because $path is used in the recursive call rather than $p
> (which seems to contain a properly transformed $path).  Anyway, I've
> attached a patch that works for me and I think is generally the right
> thing.

Patch-submitted-by: Jonathan Scott Duff
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>