Don't raise error message from cgroups if QEMU fails to start

The code to remove the cgroup after QEMU failed to startup could
be obscuring a real error from earlier on. It is not neccessary
to raise an error in this case, so tell cgroups to keep quiet

* src/qemu/qemu_driver.c: Don't raise cgroups error in QEMU start
  cleanup code.

src/qemu/qemu_driver.c

@@ -2906,7 +2906,7 @@ cleanup:
     if (driver->securityDriver &&
         driver->securityDriver->domainReleaseSecurityLabel)
         driver->securityDriver->domainReleaseSecurityLabel(vm);
-    qemuRemoveCgroup(driver, vm, 0);
+    qemuRemoveCgroup(driver, vm, 1);
     if ((vm->def->ngraphics == 1) &&
         vm->def->graphics[0]->type == VIR_DOMAIN_GRAPHICS_TYPE_VNC &&
         vm->def->graphics[0]->data.vnc.autoport)