[SSSD] [PATCHES] make enumerations a background task

[Simo Sorce]

This affects only the ldap driver.
Enumerations are now a background task, on startup a full enumeration is
performed.
Then every 5 minutes (changeable default) only new/modified entries are
retrieved.
So after the first full pull the quantity of data that is pulled is
limited, this is why I have not removed the large transaction yet.

Next step is to change the group handling code into a 2 step process, or
some group membership may be lost against server that allow nested
groups via the member/memberof schema.

0001 simplify code, no need for a wrapper
0002 The patch that changes the enumeration code

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York