Enable transactions by default, make password and modrdn TXN-aware

The password and modrdn plugins needed to be made transaction aware
for the pre and post operations.

Remove the reverse member hoop jumping. Just fetch the entry once
and all the memberof data is there (plus objectclass).

Fix some unit tests that are failing because we actually get the data
now due to transactions.

Add small bit of code in user plugin to retrieve the user again
ala wait_for_attr but in the case of transactions we need do it only
once.

Deprecate wait_for_attr code.

Add a memberof fixup task for roles.

https://fedorahosted.org/freeipa/ticket/1263
https://fedorahosted.org/freeipa/ticket/1891
https://fedorahosted.org/freeipa/ticket/2056
https://fedorahosted.org/freeipa/ticket/3043
https://fedorahosted.org/freeipa/ticket/3191
https://fedorahosted.org/freeipa/ticket/3046

ipaserver/install/dsinstance.py

@@ -202,7 +202,6 @@ class DsInstance(service.Service):
         self.step("configuring replication version plugin", self.__config_version_module)
         self.step("enabling IPA enrollment plugin", self.__add_enrollment_module)
         self.step("enabling ldapi", self.__enable_ldapi)
-        self.step("disabling betxn plugins", self.__disable_betxn)
         self.step("configuring uniqueness plugin", self.__set_unique_attrs)
         self.step("configuring uuid plugin", self.__config_uuid_module)
         self.step("configuring modrdn plugin", self.__config_modrdn_module)
@@ -476,9 +475,6 @@ class DsInstance(service.Service):
     def __add_referint_module(self):
         self._ldap_mod("referint-conf.ldif")
 
-    def __disable_betxn(self):
-        self._ldap_mod("disable-betxn.ldif", self.sub_dict)
-
     def __set_unique_attrs(self):
         self._ldap_mod("unique-attributes.ldif", self.sub_dict)