Use SFTP instead of SCP to copy file

Fix SCP not working on well with Windows guests. Switch over to
SFTP instead

test/test-manager/src/vm/provision.rs

@@ -196,20 +196,11 @@ fn ssh_send_file<P: AsRef<Path> + Copy>(
 }
 
 /// Analogues to [`std::fs::write`], but over ssh!
-fn ssh_write<P: AsRef<Path>, C: AsRef<[u8]>>(session: &Session, dest: P, source: C) -> Result<()> {
-    let bytes = source.as_ref();
+fn ssh_write<P: AsRef<Path>>(session: &Session, dest: P, mut source: impl Read) -> Result<()> {
+    let sftp = session.sftp()?;
+    let mut remote_file = sftp.create(dest.as_ref())?;
 
-    let source = &mut &bytes[..];
-    let source_len = u64::try_from(bytes.len()).context("File too large, did not fit in a u64")?;
-
-    let mut remote_file = session.scp_send(dest.as_ref(), 0o744, source_len, None)?;
-
-    io::copy(source, &mut remote_file).context("failed to write file")?;
-
-    remote_file.send_eof()?;
-    remote_file.wait_eof()?;
-    remote_file.close()?;
-    remote_file.wait_close()?;
+    io::copy(&mut source, &mut remote_file).context("failed to write file")?;
 
     Ok(())
 }