[autotest] Update gitignore to include creds/

creds will be deployed by puppet. Add it to gitignore.

TEST=None
BUG=chromium:567882

Change-Id: Iad893b5f0dbdddcf280c7ac869bb109d82da7b15
Reviewed-on: https://chromium-review.googlesource.com/318273
Commit-Ready: Fang Deng <[email protected]>
Tested-by: Fang Deng <[email protected]>
Reviewed-by: Dan Shi <[email protected]>
1 file changed