hgwebdir: ignore hgrc parse errors while building the index page
An error in the .hg/hgrc file from a repository would prevent the
following repos from being shown in the index page.
The IOError handling was unnecessary - it's already handled in
readconfig.
This should fix issue731.
The error in the .hg/hgrc file will still prevent the repo from
being exported with hgweb.
adding a
b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
a renamed from b:9a263dd772e0159ddfa70fb8a448bb6c7ec8c69f
% test with --rev
b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3