failed to init cluster if raw docker already installed

[kakaZhou719]

What happened:

failed to init cluster master0 if raw docker already installed.

thats because sealer-docker will pull images from sea.hub by default, but raw docker not.

i think we could overwrite the docker if it is already existed when run install process.

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• sealer version (use sealer version):
• Cloud provider or hardware configuration:
• OS (e.g: cat /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others: