Fix tests not removing test ldap user

Add MacOS DS_Store file to be ignored by git

.gitignore

@@ -3,3 +3,4 @@
 *.swp
 .svn
 coin/settings_local.py
+.DS_Store

coin/members/tests.py

@@ -179,6 +179,8 @@ class MemberAdminTests(TestCase):
         self.assertNotContains(edit_page,
             '''<input id="id_ldap_cn" />''',
             html=True)
+        
+        LdapUser.objects.get(pk=ldap_cn).delete();
 
 class MemberTestsUtils(object):
     @staticmethod