storage: Remove per-field update callbacks
storage: Remove per-field update callbacks

They are not used anymore.

moraleslazaro/cockpit,garrett/cockpit,cockpituous/cockpit,garrett/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,mvollmer/cockpit,deryni/cockpit,deryni/cockpit,martinpitt/cockpit,cockpituous/cockpit,cockpituous/cockpit,martinpitt/cockpit,cockpit-project/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,deryni/cockpit,cockpituous/cockpit,deryni/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,deryni/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,martinpitt/cockpit,deryni/cockpit