Fix: 5b10c4c introduced 'Cannot use object of type stdClass as array'

After pulling 5b10c4c I get a new error

[bwood@ucbmbp private]$ drush psite-tunnel parking dev
Drush command terminated abnormally due to an unrecoverable error.                                         [error]
Error: Cannot use object of type stdClass as array in /Users/bwood/.drush/terminus/terminus.tunnel.inc,
line 22

This fixes that error.