utils_libvirtd: Don't need to wait if start failed

If libvirtd service start or restart failed, just checking the exit code
will be enough, we don't need to wait 60 seconds to check whether a
virsh command can be executed.

Signed-off-by: Hao Liu <hliu@redhat.com>
Merge pull request #1713 from Hao-Liu/fix_libvirtd

utils_libvirtd: Don't need to wait if start failed