Fixed a spelling mistake. LMS-605

lms/templates/login.html

@@ -95,7 +95,7 @@
       </div>
 
       <div role="alert" class="status message submission-error" tabindex="-1">
-        <h3 class="message-title">The following errors occured while logging you in: </h3>
+        <h3 class="message-title">The following errors occurred while logging you in: </h3>
         <ul class="message-copy">
           <li>Your email or password is incorrect</li>
         </ul>