[cache] Fix Savannah bug #31923, patch drafted by Harsha.

When a node comparator changes the cached nodes during the
search of a node matching with queried properties, the
pointers obtained before the functon should be updated to
prevent the dereference to freed or reallocated nodes.
To minimize the rescan of the linked list, the update is
executed when the comparator notifies the change of cached
nodes. This change depends previous change:
38b272ffbbdaae276d636aec4ef84af407d16181

* src/cache/ftccache.h (FTC_CACHE_LOOKUP_CMP): Rescan the
top node if the cached nodes are changed.
* src/cache/ftccache.c (FTC_Cache_Lookup): Ditto.
3 files changed