files: storage: rename should check parent directories of old and new files

as described by POSIX.1-2008
(see http://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html)

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Merge pull request #9550 from kofemann/dcache-fixes-for-upstream

storage: do not check file mode on rename