BUG: smbd: return correct error in mkdir_internal

Commit - 405d1164 smbd: open a pathref fsp on the parent directory adds a TALLOC_FREE() call which clears out the errno required by the subsequent map_nt_error_from_unix() call. The errno is possibly cleared by a destructor called by the TALLOC_FREE(). This results in an incorrect nt_status being returned.

This is causing failures in smb2.create.mkdir-dup with glusterfs as the backing fs.

Fix this by calling map_nt_error_from_unix(errno) before the TALLOC_FREE() call is made.

I have tested this patch using smbtorture smb2.create.mkdir-dup test with glusterfs as the backend filesystem for both replicate and disperse volumes.

BZ: https://bugzilla.samba.org/show_bug.cgi?id=14662

Edit: Add BZ

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