Remove explicit reference to edX

This docstring will be used by other site instances, it shouldn't be specific
to the main edx.org site.

openassessment/templates/openassessmentblock/oa_uploaded_file.html

@@ -20,7 +20,7 @@
                 {% trans "View the file associated with this submission." %}
             </a>
             {% if show_warning %}
-                <p class="submission_file_warning">{% trans "(Caution: This file was uploaded by another course learner and has not been verified, screened, approved, reviewed, or endorsed by edX. If you decide to access it, you do so at your own risk.)" %}</p>
+                <p class="submission_file_warning">{% trans "(Caution: This file was uploaded by another course learner and has not been verified, screened, approved, reviewed, or endorsed by the site administrator. If you decide to access it, you do so at your own risk.)" %}</p>
             {% endif %}
         {% endif %}
     </div>