[ldapfeed] re-enable ldap tests for python 3.7

This was disabled because ldap3<2 wasn't compatible with python 3.7
While I'm here, drop unseless newline.

--HG--
branch : 3.26

cubicweb/server/test/unittest_ldapsource.py

@@ -148,12 +148,8 @@ class LDAPFeedTestBase(CubicWebTC):
 
     @classmethod
     def pre_setup_database(cls, cnx, config):
-        if sys.version_info[:2] >= (3, 7):
-            raise unittest.SkipTest(
-                'ldapfeed is not currently compatible with Python 3.7')
         cnx.create_entity('CWSource', name=u'ldap', type=u'ldapfeed', parser=u'ldapfeed',
                           url=URL, config=CONFIG_LDAPFEED)
-
         cnx.commit()
         return cls.pull(cnx)