fix some little bug

app/views/projects/_course.html.erb

@@ -56,9 +56,9 @@
 	<div class="main-language" style="margin-left: 30px;margin-top:-10px">	
 		<%= content_tag "span","#{l(:label_duration_time)}:", :class => "course-font"%>
 		<% unless Course.find_by_extra(@project.identifier).nil? %>
-		<%= DateTime.parse(Course.find_by_extra(@project.identifier).setup_time.to_s).strftime("%Y年%m月%d日").to_s unless   Course.find_by_extra(@project.identifier).setup_time.nil? %>
-		<%= '-' unless  Course.find_by_extra(@project.identifier).setup_time.nil?  %>
-		<%= DateTime.parse(Course.find_by_extra(@project.identifier).endup_time.to_s).strftime("%Y年%m月%d日").to_s unless  Course.find_by_extra(@project.identifier).endup_time.nil? %>
+		<%= DateTime.parse(Course.find_by_extra(@project.identifier).setup_time.to_s).strftime("%Y年%m月%d日").to_s unless   Course.find_by_extra(@project.identifier).setup_time.blank? %>
+		<%= '-' unless  Course.find_by_extra(@project.identifier).setup_time.blank?  %>
+		<%= DateTime.parse(Course.find_by_extra(@project.identifier).endup_time.to_s).strftime("%Y年%m月%d日").to_s unless  Course.find_by_extra(@project.identifier).endup_time.blank? %>
 		<% end %>
 	</div>
 </div>