machines: do not add a new pool entry into the global state with 'Started' signal
machines: do not add a new pool entry into the global state with 'Started' signal

This could lead to race conditions, where a pool gets added twice.

Closes #12392
deryni/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,garrett/cockpit,martinpitt/cockpit,deryni/cockpit,garrett/cockpit,moraleslazaro/cockpit,garrett/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,cockpit-project/cockpit,cockpituous/cockpit,deryni/cockpit,deryni/cockpit,cockpituous/cockpit,garrett/cockpit,cockpituous/cockpit,cockpit-project/cockpit,deryni/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpituous/cockpit,martinpitt/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,cockpituous/cockpit,garrett/cockpit,cockpit-project/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit