git-cache: fix bug in prior CL.

cwd param isn't necessary, because actual cwd is already correct --
see 'git gc' invocation below.

R=ehmaldonado, iannucci

Change-Id: Ia885ad32b11b0de37d3b0e4e5359d2031b6852d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1818455
Auto-Submit: Andrii Shyshkalov <tandrii@google.com>
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>

git_cache.py

@@ -595,8 +595,7 @@ class Mirror(object):
     # It appears core.deltaBaseCacheLimit restricts the file size of the pack
     # files produced, while we want 1 big pack file for efficiency.
     try:
-      self.RunGit(['config', '--unset-all', 'core.deltaBaseCacheLimit'],
-                  cwd=cwd)
+      self.RunGit(['config', '--unset-all', 'core.deltaBaseCacheLimit'])
     except subprocess.CalledProcessError:
       pass  # Nothing to unset is fine.
     gc_args = ['gc', '--prune=all']