hgweb: handle exception of misconfigured path on index page
If hgweb.config contains wrong path mapping, hgweb causes internal server
error on repository index page.
This patch changes makeindex() to ignore RepoError, because it looks to be
designed to suppress configuration error.
adding base
foo/renamed
renamed
bar/renamed
renamed
baz
.hg/patches/baz
new/dir
.hg/patches/new/dir
% test patch being renamed before committed