Failed to fetch system vm template

[敬林晓]

I have downloaded vm template from 
`http://download.cloudstack.org/systemvm/4.11/systemvmtemplate-4.11.2-kvm.qcow2.bz2`.

I executed the command according to the quick installation guide: 
`/usr/share/cloudstack-common/scripts/storage/secondary/cloud-install-sys-tmplt 
-m /export/secondary -u /root/systemvmtemplate-4.11.2-kvm.qcow2.bz2 -h kvm -F`

But error messages occured:
```
mysql: [Warning] Using a password on the command line interface can be insecure.
mysql: [Warning] Using a password on the command line interface can be insecure.
/root/systemvmtemplate-4.11.2-kvm.qcow2.bz2: Scheme missing.
Failed to fetch system vm template from 
/root/systemvmtemplate-4.11.2-kvm.qcow2.bz2
Installation failed
```
What does `Scheme missing` mean? What should I do to resolve the error?
My CloudStack version is 4.13.1.0 and the OS is Ubuntu 18.04.4.
Any help will be appreciated!