After function autoscaling support, it's impossible for qinling-engine
to get execution log because it doesn't know which pod it is talking
to.
So, it's neccessary for the runtime to return execution logs to
qinling engine.
The qinling client is not affected.
Change-Id: I96dfd00cc83d8b8a5e8c601ee3800b1ef1a45b1b
If update image, will send asynchronous request to engine. If some
error happened during update, engine will rollback runtime
automatically.
Change-Id: I1598b1c04427dfdb7d573bbff8dc017f113c2fd2
Lingxian Kong