fusefrontend: Set owner after symlink creation in PlaintextNames mode
fusefrontend: Set owner after symlink creation in PlaintextNames mode

This is already done in regular mode, but was missing when PlaintextNames mode
is enabled. As a result, symlinks created by non-root users were still owned
by root afterwards.

Fixes https://github.com/rfjakob/gocryptfs/issues/176

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