config: make sure core.ignoreCase is false

config: make sure core.ignoreCase is false

In a hosting situation, even on case insensitive hosts, it is
imperative that core.ignoreCase be disabled otherwise when fetching
remote updates, especially when using fast-import mirrors, information
can be lost.

This never causes a problem because files are never checked out in
the bare hosting repositories.  Furthermore, even if core.ignoreCase
was allowed to be true, ref name collisions (ref names that differ only
in case) can still happen so there's nothing to be gained by ever allowing
it to be true especially since that can lead to information loss when
using a fast-import mirror.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>