[34078525] Makes OpenID provider login box modal.

lms/templates/provider_login.html

 <%inherit file="main.html" />
 <%namespace name='static' file='static_content.html'/>
 
-<style>
-
+<%block name="headextra">
+<style type="text/css">
 .openid-login {
     display: block;
     position: relative;
     left: 0;
     margin: 100px auto;
     top: 0;
+    z-index: 200;
 }
 
 .openid-login input[type=submit] {
@@ -16,7 +17,17 @@
     height: auto !important;
 }
 
+#lean_overlay {
+  display: block;
+  position: fixed;
+  left: 0px;
+  top: 0px;
+  z-index: 100;
+  width:100%;
+  height:100%;
+}
 </style>
+</%block>
 
 <section id="login-modal" class="modal login-modal openid-login">
   <div class="inner-wrapper">
@@ -38,3 +49,4 @@
     </form>
   </div>
 </section>
+<div id="lean_overlay"></div>