In ntfs_init_fs_context we allocate memory in fc->s_fs_info.
In case of failed mount we must free it in ntfs_fill_super.
We can't do it in ntfs_fs_free, because ntfs_fs_free called
with fc->s_fs_info == NULL.
fc->s_fs_info became NULL in sget_fc.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>