修改《分组名可以为空格》bug

Signed-off-by: alan <547533434@qq.com>

app/views/courses/_groups_name.html.erb

@@ -6,8 +6,8 @@
         }
     }
     function validate_groupname_null(value1) {
-
-        if(value1.length == 0) {
+         value1 = value1.trim();
+        if(value1.length == 0 ) {
             alert('<%= l(:label_limit_groupname_null) %>');
         }
     }