Update integration test userns support with flag name change

`--root` is now `--userns-remap`

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Upstream-commit: a85e6a4d4a5afc866b153e46e19ed3c15d3a24ec
Component: engine

components/engine/hack/make/.integration-daemon-start

@@ -29,7 +29,7 @@ fi
 # example usage: DOCKER_STORAGE_OPTS="dm.basesize=20G,dm.loopdatasize=200G"
 extra_params=""
 if [ "$DOCKER_REMAP_ROOT" ]; then
-	extra_params="--root $DOCKER_REMAP_ROOT"
+	extra_params="--userns-remap $DOCKER_REMAP_ROOT"
 fi
 
 if [ -z "$DOCKER_TEST_HOST" ]; then

components/engine/integration-cli/docker_utils.go

@@ -108,7 +108,7 @@ func (d *Daemon) Start(arg ...string) error {
 	)
 
 	if root := os.Getenv("DOCKER_REMAP_ROOT"); root != "" {
-		args = append(args, []string{"--root", root}...)
+		args = append(args, []string{"--userns-remap", root}...)
 	}
 
 	// If we don't explicitly set the log-level or debug flag(-D) then