[service-vm] Send shutdown request to exit rialto

And rialto will be in a loop of processing request till receiving
the shutdown request.

Bug: 299432766
Test: atest rialto_test
Change-Id: Ifd65adde74a370a91fc462930bb513a3e1fe65b9
diff --git a/virtualizationservice/src/rkpvm.rs b/virtualizationservice/src/rkpvm.rs
index 2c9230b..dbadd60 100644
--- a/virtualizationservice/src/rkpvm.rs
+++ b/virtualizationservice/src/rkpvm.rs
@@ -26,7 +26,7 @@
     // TODO(b/271275206): Send the correct request type with client VM's
     // information to be attested.
     let request = Request::Reverse(csr.to_vec());
-    match vm.process_request(&request).context("Failed to process request")? {
+    match vm.process_request(request).context("Failed to process request")? {
         Response::Reverse(cert) => Ok(cert),
         _ => bail!("Incorrect response type"),
     }