provisioning: fixes typo

pkg/models/dashboards.go

@@ -32,7 +32,7 @@ var (
 	ErrDashboardUpdateAccessDenied             = errors.New("Access denied to save dashboard")
 	ErrDashboardInvalidUid                     = errors.New("uid contains illegal characters")
 	ErrDashboardUidToLong                      = errors.New("uid to long. max 40 characters")
-	ErrDashboardCannotSaveProvisionedDashboard = errors.New("Cannot save provisioned dashboards")
+	ErrDashboardCannotSaveProvisionedDashboard = errors.New("Cannot save provisioned dashboard")
 	ErrDashboardProvisioningDoesNotExist       = errors.New("Dashboard provisioning does not exist")
 	RootFolderName                             = "General"
 )