Update trivial-validate.py

blackout@h2o-Arch ~/tmp/https-everywhere-electrolysis % ./makexpi.sh 
  File "utils/trivial-validate.py", line 71
    if not rule.get("to"):
                         ^
TabError: inconsistent use of tabs and spaces in indentation
ERROR: Validation of rulesets failed.

format error on line 71.
formatted whole file to pep8