[gclient_scm] Delete auto configure in gclient

This causes more trouble than it's worth (it's breaking dawn builds).

That does mean for a fresh depot_tools install, users will need to
explicitly run git cl creds-check once, which means tracking down all
of the docs that need to say that.

In the meantime, it's probably better to delete this now.

Bug: 408427309
Change-Id: I5595756441500c43c543b47d97ff6b1bd9ddab30
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6434734
Commit-Queue: Allen Li <ayatane@chromium.org>
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>

gclient_scm.py

@@ -1371,16 +1371,6 @@ class GitWrapper(SCMWrapper):
         parent_dir = os.path.dirname(self.checkout_path)
         gclient_utils.safe_makedirs(parent_dir)
 
-        # Set up Git authentication configuration that is needed to clone/fetch the repo.
-        #
-        # Disabled on Windows
-        if newauth.Enabled() and os.name != 'nt':
-            # We need the host from the URL to determine auth settings.
-            # The url parameter might have been re-written to a local
-            # cache directory, so we need self.url, which contains the
-            # original remote URL.
-            git_auth.ConfigureGlobal('/', self.url)
-
         if hasattr(options, 'no_history') and options.no_history:
             self._Run(['init', self.checkout_path], options, cwd=self._root_dir)
             self._Run(['remote', 'add', 'origin', url], options)