Introduction of a new function in the LRU cache source file.
Purpose of this function is to be used to delete a number of entries in
the cache. 'number' is defined by the caller and the key removed are
taken at the tail of the tree
It lookup a key in a LRU cache for use with specified domain and revision. It
differs from lru64_get as it does not create missing keys. The function returns
NULL if an error or a cache miss occurs.
Now, When a item is committed in an LRU tree, you can define a function to free
data owned by this item. This function will be called when the item is removed
from the LRU tree or when the tree is destroyed..
This will be usable to implement some maps/acl caches for heavy datasets
loaded from files (mostly regex-based but in general anything that cannot
be indexed in a tree).
