Wipe configchecksums also on assignment changes

If an assignemnt is changed to switch a backend from
one configuration to another, we would still send configuration requests
using the old checksum.
The server will respond with `NotModified` and we don't try to restart
the backend.

Instead of also resetting the checksum when we update the assignment
store, simply wipe the entire checksum map if either the assignment
or the backends have changed.

Fixes #352

daemon/daemon.go

@@ -111,7 +111,7 @@ func (dc *DaemonConfig) GetRunnerByBackendId(id string) Runner {
 	return nil
 }
 
-func (dc *DaemonConfig) SyncWithAssignments(configChecksums map[string]string, context *context.Ctx) {
+func (dc *DaemonConfig) SyncWithAssignments(context *context.Ctx) {
 	if dc.Runner == nil {
 		return
 	}
@@ -125,7 +125,6 @@ func (dc *DaemonConfig) SyncWithAssignments(configChecksums map[string]string, c
 			log.Infof("[%s] Updating process configuration", runner.Name())
 			runnerServiceType := runnerBackend.ServiceType
 			runner.SetBackend(*backend)
-			configChecksums[backend.Id] = ""
 			if backend.ServiceType != runnerServiceType {
 				log.Infof("Changing process runner (%s -> %s) for: %s",
 					runnerServiceType, backend.ServiceType, backend.Name)
@@ -146,7 +145,6 @@ func (dc *DaemonConfig) SyncWithAssignments(configChecksums map[string]string, c
 		if backend == nil || assignments.Store.GetAll()[backend.Id] == "" {
 			log.Info("Removing process runner: " + backend.Name)
 			dc.DeleteRunner(id)
-			configChecksums[backend.Id] = ""
 		}
 	}
 	assignedBackends := []*backends.Backend{}

services/periodicals.go

@@ -60,8 +60,9 @@ func StartPeriodicals(context *context.Ctx) {
 
 			if !response.NotModified || !backendResponse.NotModified {
 				assignments.Store.Update(response.Assignments)
+				configChecksums = make(map[string]string)
 				// create process instances
-				daemon.Daemon.SyncWithAssignments(configChecksums, context)
+				daemon.Daemon.SyncWithAssignments(context)
 				// test for new or updated configurations and start the corresponding collector
 				if assignments.Store.Len() == 0 {
 					if logOnce {