qemuProcessLaunch: Return earlier if spawning qemu failed

If spawning qemu fails then we report an error and proceed to
writing status XML onto the disk. This is unnecessary as we are
sure that the domain is not running.

At the same time, if virPidFileReadPath() fails it returns
-errno. Use it in the error message. It may explain what went
wrong.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_process.c

@@ -6695,16 +6695,18 @@ qemuProcessLaunch(virConnectPtr conn,
 
     /* wait for qemu process to show up */
     if (rv == 0) {
-        if (virPidFileReadPath(priv->pidfile, &vm->pid) < 0) {
-            virReportError(VIR_ERR_INTERNAL_ERROR,
-                           _("Domain %s didn't show up"), vm->def->name);
-            rv = -1;
+        if ((rv = virPidFileReadPath(priv->pidfile, &vm->pid)) < 0) {
+            virReportSystemError(-rv,
+                                 _("Domain %s didn't show up"),
+                                 vm->def->name);
+            goto cleanup;
         }
         VIR_DEBUG("QEMU vm=%p name=%s running with pid=%lld",
                   vm, vm->def->name, (long long)vm->pid);
     } else {
         VIR_DEBUG("QEMU vm=%p name=%s failed to spawn",
                   vm, vm->def->name);
+        goto cleanup;
     }
 
     VIR_DEBUG("Writing early domain status to disk");