chameleond: v3: make it compatible with python3.7

make some format string compatible with python3.7.

BUG=b:224440893
TEST=make&&make remote-install CHAMELEON_HOST=${IP}

Change-Id: I725278880ef1e75840839e6ce4658871166a8fa2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/chameleon/+/3524289
Reviewed-by: Alexandru Stan <amstan@chromium.org>
Reviewed-by: Shyh-In Hwang <josephsih@chromium.org>
Commit-Queue: John Lai <johnlai@google.com>
Tested-by: John Lai <johnlai@google.com>
1 file changed