Revert "fusefrontend: don't always clear the dircache in Rename"
Revert "fusefrontend: don't always clear the dircache in Rename"

As noticed by @slackner in
https://github.com/rfjakob/gocryptfs/commit/cb8872577d66ff0fc38bcd70493be06bc0f34ffa#commitcomment-39405233 ,
this is not safe.

This reverts commit cb8872577d66ff0fc38bcd70493be06bc0f34ffa.

rfjakob/gocryptfs,rfjakob/gocryptfs,rfjakob/gocryptfs,rfjakob/gocryptfs