fix reference to $sumo_json_source_path

[drewrothstein]

With usage like this:

class { 'sumo':
    accessid           => 'REDACTED',
    accesskey          => 'REDACTED',
    manage_sources     => true,
    manage_config_file => true,
}

Prior to fixing:

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Evaluation Error: Unknown variable: 'sumo_json_source_path'. at /etc/puppetlabs/code/environments/production/modules/sumo/manifests/nix_config.pp:41:18 on node puppet

After fixing:

Notice: /Stage[main]/Sumo::Nix_config/File[/usr/local/sumo]/ensure: created
Notice: /Stage[main]/Sumo::Nix_config/File[/usr/local/sumo/sumo.json]/ensure: defined content as '{md5}304694fe3fd0b96e91dc8dcab2b5e8e8'
Notice: /Stage[main]/Sumo::Nix_config/File[/etc/sumo.conf]/ensure: defined content as '{md5}db80e902cf1f591b844e348f33dc4b2d'
Notice: /Stage[main]/Sumo::Nix_config/Exec[Download Sumo Executable]/returns: executed successfully
Notice: /Stage[main]/Sumo::Nix_config/Exec[Execute sumo]/returns: executed successfully
Notice: Applied catalog in 39.79 seconds

[duchatran]

thanks for contributing @drewrothstein !