Need to chech to make sure the StateEnvProvider is set before using. (#1826)

Author: ben-of-codecraft

Diff for: libs/scheduler/aws.go

@@ -185,10 +185,12 @@ func(job *Job) AuthBackendConfig() error {
 
 func(job *Job) AuthTerragrunt() error {
 	var err error
-	job.StateEnvVars, err = populateKeys(job.StateEnvVars, *job.StateEnvProvider)
-	if err != nil {
-		log.Printf("Failed to get keys from role (StateEnvProvider): %v", err)
-		return fmt.Errorf("failed to get (state) keys from role: %v", err)
+	if(job.StateEnvProvider != nil) {
+		job.StateEnvVars, err = populateKeys(job.StateEnvVars, *job.StateEnvProvider)
+		if err != nil {
+			log.Printf("Failed to get keys from role (StateEnvProvider): %v", err)
+			return fmt.Errorf("failed to get (state) keys from role: %v", err)
+		}
 	}
 
 	if job.CommandEnvProvider != nil {