token or empty string

[silppuri]

Fixes bug when projects did not yet have flow-tokens

ActionView::Template::Error (can't convert Symbol into Integer):
    3: <% Project.active.each do |project| %>
    4: <p>
    5:   <%= content_tag(:label, project.name) %>
    6:   <%= text_field_tag("settings[api_token][#{project.identifier}]", @settings[:api_token][project.identifier]) %>
    7: </p>
    8: <% end %>
  app/views/settings/plugin.html.erb:6:in `block in _app_views_settings_plugin_html_erb__3383405472618272837_48057540'
  app/views/settings/plugin.html.erb:4:in `_app_views_settings_plugin_html_erb__3383405472618272837_48057540'