9a2d462e7b
libssh2_sftp_fsync is an extension to libssh2 to support fsync(2) over sftp, which is itself an extension of OpenSSH. If both libssh2 and the ssh daemon support it, this will allow bdrv_flush_to_disk to commit changes through to disk on the remote server. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>