Don't check symlinks for license headers

Because it tried to open the symlink and caused an error. So ignore symlinks.

BUG=None
TEST=tried uploading a CL with a symlink
TEST=`./pre-upload_unittest.py` passes

Change-Id: I07f2394a832d82e692fbe5ec4d3ec270a671dcaa
Reviewed-on: https://chromium-review.googlesource.com/188072
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Wai-Hong Tam <waihong@chromium.org>
Tested-by: Wai-Hong Tam <waihong@chromium.org>
1 file changed