fromupstream: eliminate '\' by parentheses

BUG=None
TEST=1. cros lint fromupstream.py
2. fromupstream.py -b none -t none -d pw://11123203
3. fromupstream.py -b none -t none -d linux://d85f6b93a76e
4. fromupstream.py -b none -t none -d git://mark/for-next/96ed76983307
5. fromupstream.py -b none -t none -d https://cros#master/eb8e661

Change-Id: I6acd61f26f5dbc6c861a64e28f250a21eb8ad18c
Signed-off-by: Tzung-Bi Shih <tzungbi@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/1784029
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed