fix:EZP-22917 when cache removal fails, no message is displayed

link: https://jira.ez.no/browse/EZP-22917

description: if a remove cache operation in the legacy kernel fails, there are no warnings in log, messages or any display of the failed result at all.
the ezDir::recursiveDelete() returns "false" on failure, but this result is not used. also, the function itself does not issue any warning or error to the logs.
tests:
manually modify a folder (symlink, location, permission) and clear caches