Use os.path.normcase in git-sync-deps

Avoid strange issues with path case insensitivity on Windows with
os.path.normcase.

Change-Id: I9327ba9c22cf5e3ff66b49af56bedd223b24efd4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/556025
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed