Rationalize the git config settings for index-pack performance.

fetch.py

Index: fetch.py
diff --git a/fetch.py b/fetch.py
index 8b84c9937a7814c81a476de9d2054abfc28cc4cd..dfd038641b7d18cf17b0c5aa55eefc6b35502482 100755
--- a/fetch.py
+++ b/fetch.py
@@ -109,9 +109,6 @@ class GclientGitCheckout(GclientCheckout, GitCheckout):
     return os.path.exists(os.path.join(os.getcwd(), self.root))
 
   def init(self):
-    # TODO(dpranke): Work around issues w/ delta compression on big repos.
-    self.run_git('config', '--global', 'core.deltaBaseCacheLimit', '1G')
-
     # Configure and do the gclient checkout.
     self.run_gclient('config', '--spec', self.spec['gclient_spec'])
     if self.options.nohooks: