hgweb: do not pass on repo.ui when recreating a repo
Recreate the repo with the global configuration in repo.baseui. The repo
configuration is reread anyway. And now deleted repo configuration is reset to
the default value.
# The 9diff extdiff command generates diff(1) compatible output
# suitable for use with the plumber(4).
[extensions]
extdiff =
[extdiff]
9diff = 9diff -cm $parent $child $root