gyp_skia: use path python, be quiet

/usr/bin/python might not be python 2.x

I'm getting annoyed by scripts printing messages when there's no problem.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1716493003

Review URL: https://codereview.chromium.org/1716493003
1 file changed