qemu: return -1 on error paths in qemuDomainSaveImageStartVM

Error paths after sending the event that domain is started written as if ret = -1
which is set at the beginning of the function. It's common idioma to keep 'ret'
equal to -1 until the end of function where it is set to 0. But here we use ret
to keep result of restore operation too and thus breaks the idioma and its users :)

Let's use different variable to hold restore result.
Signed-off-by: NNikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>

src/qemu/qemu_driver.c

@@ -6732,6 +6732,7 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
                            qemuDomainAsyncJob asyncJob)
 {
     int ret = -1;
+    bool restored = false;
     virObjectEventPtr event;
     int intermediatefd = -1;
     virCommandPtr cmd = NULL;
@@ -6758,13 +6759,14 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
     }
 
     /* Set the migration source and start it up. */
-    ret = qemuProcessStart(conn, driver, vm, asyncJob,
-                           "stdio", *fd, path, NULL,
-                           VIR_NETDEV_VPORT_PROFILE_OP_RESTORE,
-                           VIR_QEMU_PROCESS_START_PAUSED);
+    if (qemuProcessStart(conn, driver, vm, asyncJob,
+                         "stdio", *fd, path, NULL,
+                         VIR_NETDEV_VPORT_PROFILE_OP_RESTORE,
+                         VIR_QEMU_PROCESS_START_PAUSED) == 0)
+        restored = true;
 
     if (intermediatefd != -1) {
-        if (ret < 0) {
+        if (!restored) {
             /* if there was an error setting up qemu, the intermediate
              * process will wait forever to write to stdout, so we
              * must manually kill it.
@@ -6775,7 +6777,7 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
 
         if (virCommandWait(cmd, NULL) < 0) {
             qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED, 0);
-            ret = -1;
+            restored = false;
         }
         VIR_DEBUG("Decompression binary stderr: %s", NULLSTR(errbuf));
     }
@@ -6783,18 +6785,16 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
 
     if (VIR_CLOSE(*fd) < 0) {
         virReportSystemError(errno, _("cannot close file: %s"), path);
-        ret = -1;
+        restored = false;
     }
 
-    if (ret < 0) {
-        virDomainAuditStart(vm, "restored", false);
+    virDomainAuditStart(vm, "restored", restored);
+    if (!restored)
         goto cleanup;
-    }
 
     event = virDomainEventLifecycleNewFromObj(vm,
                                      VIR_DOMAIN_EVENT_STARTED,
                                      VIR_DOMAIN_EVENT_STARTED_RESTORED);
-    virDomainAuditStart(vm, "restored", true);
     qemuDomainEventQueue(driver, event);