VOL-2639: Creation of common errors package

Change-Id: Iac2ab83826bf072c84af81e9e2bccf61d40c07ed
diff --git a/internal/pkg/core/olt_state_transitions_test.go b/internal/pkg/core/olt_state_transitions_test.go
index 75e7807..9c2be8d 100644
--- a/internal/pkg/core/olt_state_transitions_test.go
+++ b/internal/pkg/core/olt_state_transitions_test.go
@@ -18,6 +18,7 @@
 
 import (
 	"context"
+	"github.com/opencord/voltha-openolt-adapter/internal/pkg/olterrors"
 	"reflect"
 	"testing"
 	"time"
@@ -47,7 +48,7 @@
 		after: []TransitionHandler{func(ctx context.Context) error {
 			return nil
 		}, func(ctx context.Context) error {
-			return ErrStateTransition
+			return olterrors.ErrStateTransition
 		}},
 	}
 	transitions[GrpcConnected] = transition
@@ -65,7 +66,7 @@
 		before: []TransitionHandler{func(ctx context.Context) error {
 			return nil
 		}, func(ctx context.Context) error {
-			return ErrStateTransition
+			return olterrors.ErrStateTransition
 		}},
 	}
 	transitions[GrpcConnected] = transition