Ticket 49031 - Improve memberof with a cache of ancestors for groups
During a group update, memberof computes the ancestors of all impacted
leafs and groups. To compute the ancestors it lookup recursively and so
is going to compute the ancestors of a given group as many times there are
impacted nodes under that group.
The ticket implements a cache. It contains for a given group all its
ancestors, so that if it is needed to recompute the ancestors of that
group it will take it from the cache.
Reviewed by: William Brown (thanks !!!!!)
Platforms tested: F24
Flag Day: no
Doc impact: no