Delete LOCK from MySQL

[whywaita]

myshoes check the status of LOCK in MySQL during starting.

myshoes/cmd/server/cmd.go

Line 78 in a0c7eab

if err := m.ds.GetLock(ctx); err != nil {

But this implementation has a bug. A deadlock occurred in some environments like Kubernetes (from high-frequency restart).

[whywaita]

Proposal:

• Add new column owner to job
  • myshoes will update CONNECTION_ID() in MySQL.