修复当学生被剔除课程成员时，消息页面报错的bug.

app/views/users/_user_message_course.html.erb

@@ -350,7 +350,7 @@
               </li>
               <li class="homepageNewsPubType fl">
                 <%= link_to ma.course_message.user.lastname + ma.course_message.user.firstname +
-                                    "#{ma.course_message.user.members.where("course_id=?", ma.course.id).first.roles.first.name=='Student'?"同学":"老师"}",
+                                    "#{ma.course_message.user.allowed_to?(:as_teacher, ma.course) ? "老师":"同学"}",
                             user_path(ma.course_message.user), :class => "newsBlue homepageNewsPublisher" %>
                 <span class="<%= ma.viewed == 0 ? "homepageNewsTypeNotRead fl" : "homepageNewsType fl" %>">回复了作品评论：</span>
               </li>
@@ -435,19 +435,16 @@
           </a></li>
           <li class="homepageNewsPubType fl">
             <%= link_to User.find(ma.course_message_id), user_path(ma.course_message_id), :class => "newsBlue homepageNewsPublisher" %>
-            <span class="<%= ma.viewed == 0 ? "homepageNewsTypeNotRead fl" : "homepageNewsType fl" %>">申请成为您课程的<%= ma.content %>
+            <span class="<%= ma.viewed == 0 ? "homepageNewsTypeNotRead fl" : "homepageNewsType fl" %>">申请成为您课程的<%= ma.content %>：</span>
-              ：</span>
           </li>
           <li class="homepageNewsContent fl"><a href="javascript:void(0);" class="newsGrey">
-            <%= link_to "课程名称：" + ma.course, course_path(ma.course),
+            <%= link_to "课程名称：" + ma.course.name, course_path(ma.course),
                         :class => "#{ma.viewed==0 ? "newsBlack" : "newsGrey"}",
                         :onmouseover => "message_titile_show($(this),event)",
                         :onmouseout => "message_titile_hide($(this))" %></a></li>
           <div style="display: none" class="message_title_red system_message_style">
             <p>申请人资料：</p>
-
             <p>姓名：<%= User.find(ma.course_message_id).show_name %></p>
-
             <p>职称：<%= User.find(ma.course_message_id).show_name %></p>
           </div>
           <li class="homepageNewsTime fl"><%= time_tag(ma.created_at).html_safe %> </li>