Btrfs: Send: preserve ownership (uid and gid) also for symlinks.

This patch also requires a change in the user-space part of "receive".
We need to use "lchown" instead of "chown". We will do this in the
following patch.

Signed-off-by: Alex Lyakas <alex.btrfs@zadarastorage.com>

 	if (S_ISREG(sctx->cur_inode_mode)) {