all: fix usage of some variables

Signed-off-by: Alexander Morozov <lk4d4@docker.com>
(cherry picked from commit 57e14714ee)
Signed-off-by: Tibor Vass <tibor@docker.com>

libcontainerd/client_windows.go

@@ -296,9 +296,8 @@ func (clnt *client) Signal(containerID string, sig int) error {
 	} else {
 		// Terminate Process
 		if err := cont.hcsProcess.Kill(); err != nil {
+			// ignore errors
 			logrus.Warnf("Failed to terminate pid %d in %s: %q", cont.systemPid, containerID, err)
-			// Ignore errors
-			err = nil
 		}
 	}
 

plugin/backend.go

@@ -118,7 +118,7 @@ func (pm *Manager) Push(name string, metaHeader http.Header, authConfig *types.A
 	_, err = distribution.Push(name, pm.registryService, metaHeader, authConfig, config, rootfs)
 	// XXX: Ignore returning digest for now.
 	// Since digest needs to be written to the ProgressWriter.
-	return nil
+	return err
 }
 
 // Remove deletes plugin's root directory.