Bug 1496080 - Fix ./mach eslint --fix. r=ahal

Insert the argument in the correct place when passing to node.

Differential Revision: https://phabricator.services.mozilla.com/D7609

--HG--
extra : moz-landing-system : lando

tools/lint/eslint/__init__.py

@@ -74,7 +74,7 @@ def lint(paths, config, binary=None, fix=None, setup=None, **lintargs):
 
     # eslint requires that --fix be set before the --ext argument.
     if fix:
-        cmd_args.insert(1, '--fix')
+        cmd_args.insert(2, '--fix')
 
     shell = False
     if os.environ.get('MSYSTEM') in ('MINGW32', 'MINGW64'):