Ensuring endpoint resources are freed even on delete failures

Came across a code path where we might not be releasing ip
address assigned to an endpoint if we have a failure with
deleteEndpoint. Even if there is a failure it is better to
release the resource rather than holding them. This might
lead to issues where ip never gets released even though
the container has exited and the only way of recovery is a
reload.

Signed-off-by: Abhinandan Prativadi <abhi@docker.com>

Author: abhi

endpoint.go

@@ -822,7 +822,7 @@ func (ep *endpoint) Delete(force bool) error {
 		}
 	}
 
-	if err = n.getController().deleteFromStore(ep); err != nil {
+	if err = n.getController().deleteFromStore(ep); err != nil && !force {
 		return err
 	}
 

sandbox.go

@@ -182,7 +182,7 @@ func (sb *sandbox) Statistics() (map[string]*types.InterfaceStatistics, error) {
 }
 
 func (sb *sandbox) Delete() error {
-	return sb.delete(false)
+	return sb.delete(true)
 }
 
 func (sb *sandbox) delete(force bool) error {