Update /faq page: change certificate of completion to mastery

lms/templates/static_templates/faq.html

@@ -39,7 +39,7 @@
         </article>
         <article class="response">
           <h3>Will certificates be awarded?</h3>
-          <p>Yes. Online learners who demonstrate mastery of subjects can earn a certificate of completion. Certificates will be issued by edX under the name of the underlying "X University" from where the course originated, i.e. HarvardX, <em>MITx</em> or BerkeleyX.  For the courses in Fall 2012, those certificates will be free.  There is a plan to charge a modest fee for certificates in the future.</p>
+          <p>Yes. Online learners who demonstrate mastery of subjects can earn a certificate of mastery. Certificates will be issued by edX under the name of the underlying "X University" from where the course originated, i.e. HarvardX, <em>MITx</em> or BerkeleyX.  For the courses in Fall 2012, those certificates will be free.  There is a plan to charge a modest fee for certificates in the future.</p>
         </article>
         <article class="response">
           <h3>What will the scope of the online courses be? How many? Which faculty?</h3>