vm-migration: stop sending abandon after error response

When the receiver of a live migration encounters an error, it sends an
error response. The sender of the migration would then send an abandon
request and wait for a response. This abandon request is not necessary,
because the receiver already abandoned the migration due to the error it
encountered.

From now on this function will not send an abandon request to the
receiver anymore, thus it was renamed to "ok_or_error".

Also, this case was always broken, because after sending the error
response, the receiver just exits without waiting for the additional
abandon request.

On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>

vmm/src/migration/transport.rs

@@ -1115,9 +1115,7 @@ pub(crate) fn expect_ok_response(
     socket: &mut SocketStream,
     error: MigratableError,
 ) -> Result<(), MigratableError> {
-    Response::read_from(socket)?
-        .ok_or_abandon(socket, error)
-        .map(|_| ())
+    Response::read_from(socket)?.ok_or_error(error).map(|_| ())
 }
 
 /// Send a request and validate that the peer responds with OK.

vmm/src/vm.rs

@@ -3026,10 +3026,9 @@ impl Vm {
                 .context("Error sending memory fd")
                 .map_err(MigratableError::MigrateSend)?;
 
-            Response::read_from(socket)?.ok_or_abandon(
-                socket,
-                MigratableError::MigrateSend(anyhow!("Error during memory fd migration")),
-            )?;
+            Response::read_from(socket)?.ok_or_error(MigratableError::MigrateSend(anyhow!(
+                "Error during memory fd migration"
+            )))?;
         }
 
         Ok(())