Remove tools/clang from .gitignore

This used to be in DEPS a long time ago but has been removed. Remove it
from the .gitignore to clean it up and also remind those with really old
local working directories to remove it. The thing brought in by the old
DEPS has a file named "windows.h" which got confusing.

Change-Id: I6010473f9d0629ecbf6362ba3349fce2a40e3754
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/213823
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed