Updated to use app_slug, not slug for resume step

mkt/developers/templates/developers/addons/listing/item_actions.html

@@ -3,7 +3,7 @@
 {% if addon.is_incomplete() %}
   {% if check_addon_ownership(request, addon, dev=True) %}
     <li>
-      <a href="{{ url('submit.app.resume', addon.slug) }}" class="tooltip"
+      <a href="{{ url('submit.app.resume', addon.app_slug) }}" class="tooltip"
          title="{{ _("Resume the submission process for this add-on.")}}">
       {{ _('Resume') }}</a>
     </li>

mkt/developers/templates/developers/versions/list.html

@@ -22,7 +22,7 @@
                 Mozilla Marketplace. You may re-enable it at any time below.") }}
       {% elif addon.status == amo.STATUS_NULL %}
         {{ status(loc('This app is <b>incomplete</b>.')|safe) }}
-        <a href="{{ url('submit.app.resume', addon.slug) }}">
+        <a href="{{ url('submit.app.resume', addon.app_slug) }}">
           {{ _('Please complete your app.') -}}
         </a>
       {% elif addon.status == amo.STATUS_PENDING %}