fusefrontend: use Getdents if available
fusefrontend: use Getdents if available

Getdents avoids calling Lstat on each file.

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